Primes

[Gargamel]

We shoulda done this from the start... but non pics are still acceptable!    Because soon we'll run out of good pics with the number in them...

 

[Lapis]

907

gap of 78 mwahahahahhahahahaha

ps. this website might be better for a cheatsheet : http://compoasso.free.fr/primelistweb/page/prime/liste_online_en.php

 

Edited December 20, 2018 by lapis

[Gargamel]

2 minutes ago, lapis said:

907

And we were on a roll...

And since the next prime has become a number that represents so much to our modern world... I'll go with two pics:

 

 

 

[Regor]

3 hours ago, Gargamel said:

And we were on a roll...

And since the next prime has become a number that represents so much to our modern world... I'll go with two pics:

 

 

 

Going back to real life, 

 

839

[Xurkitree]

nope its 919

4 hours ago, mabdi36 said:

Going back to real life, 

 

839

 

[Green Baron]

This is becoming a mess

It is 853 now. I join the club of 14, @Gargamel :-)

 

Edit: i think i get it: @lapis, you read the list you posted per column, but you must read it per row. Might that be the cause ?

Edited December 20, 2018 by Green Baron

[YNM]

10 hours ago, Gargamel said:

I'll go with two pics:

While "two" is a prime, "two pics" is a variable.

10 hours ago, lapis said:

907

gap of 78 

Fake news !

Anyway, current prime : 857

[Green Baron]

A small step for a human:

Spoiler

#include <stdio.h>

static inline int isPrime( int n ) {
	if( 0 == ( n % 2 ) )
		return 0;
	if( 0 == ( n % 3 ) )
		return 0;
	if( 0 == ( n % 5 ) )
		return 0;
	int l = n/2;
	for( int c = 5; c <= l; ++c ) {
		if( 0 == ( n % c ) ) {
			//printf( "%d is divisable by %d\n", n, c );
			return 0;
		}
	}
	return 1;
}

int main( void ) {
    // Edit these numbers to pick a range for calculation:
	for( int n = 830; n < 900; ++n )
		if( 1 == isPrime( n ) )
			printf( "%d is prime.\n", n );
	puts( "The end !\n" );
	fflush( stdout );
	return 0;
}

 

Don't laugh about its primitiveness , but to anybody with a c compiler (all linux users) this might be helpful and a play inside the game :-) Ping me if you like a command line version like "printprime lower upper".

 

 

Edited December 20, 2018 by Green Baron

[Xurkitree]

863

[Green Baron]

[53miner53]

[Mad Rocket Scientist]

883

6 hours ago, Green Baron said:

[...]

  Reveal hidden contents

#include <stdio.h>

static inline int isPrime( int n ) {
	if( 0 == ( n % 2 ) )
		return 0;
	if( 0 == ( n % 3 ) )
		return 0;
	if( 0 == ( n % 5 ) )
		return 0;
	int l = n/2;
	for( int c = 5; c <= l; ++c ) {
		if( 0 == ( n % c ) ) {
			//printf( "%d is divisable by %d\n", n, c );
			return 0;
		}
	}
	return 1;
}

int main( void ) {
    // Edit these numbers to pick a range for calculation:
	for( int n = 830; n < 900; ++n )
		if( 1 == isPrime( n ) )
			printf( "%d is prime.\n", n );
	puts( "The end !\n" );
	fflush( stdout );
	return 0;
}

 

Don't laugh about its primitiveness , but to anybody with a c compiler (all linux users) this might be helpful and a play inside the game :-) Ping me if you like a command line version like "printprime lower upper".

 

 

This way is a bit faster and keeps track of gaps:

import math
#import matplotlib.pyplot as plt

def isprime(number):
    if number == 1:
        return False
    elif number < 4:
        return True
    elif number % 2 == 0:
        return False
    elif number < 9:
        return True
    elif number % 3 == 0:
        return False
    else:
        i = 5
        while i <= math.ceil(math.sqrt(number + 0.5)):
            if number % i == 0:
                return False
            if number % (i + 2) == 0:
                return False
            i += 6
        return True

prev_prime = 0
prime = 0
gap = 0
max_gap = 0
primes = []
gaps = []

for i in range(1, 10000):
    prev_prime = prime
    if isprime(i):
        prime = i
    gap = prime - prev_prime
    #primes.append(prime)
    #gaps.append(gap)
    if gap >= max_gap:
        max_gap = gap
        print("the primes:")
        print(prev_prime)
        print(prime)
        print("The gap")
        print(gap)

#plt.bar(primes, gaps, width=5)
#plt.show()
print(max_gap)

 

[Green Baron]

Yep, i wanted to keep it simple because a few people here asked lately what it takes to begin coding, because its not directly understandable why the root suffices (at least to me) :-)

 

Edited December 20, 2018 by Green Baron

[Delay]

Someone please make a website where you enter a (prime) number and it gives you a random picture with that number and ONLY that number in it.

Please.

[Green Baron]

duckduckgo.com, search pictures xxx.

Oops rule violation. I must wait with a new number until somebody else has posted a number.

Edited December 20, 2018 by Green Baron

[Gargamel]

I think I'm enacting the 1 week ban on @lapis for that faux pas!  Shame!

 

Hey thats a gap of 20!!! Wooot!

Edited December 21, 2018 by Gargamel

[YNM]

(note the TOPS number - 91 121; additionally 91121 is a prime as well !)

Edited December 21, 2018 by YNM

[qzgy]

Google gave me this very randomly related image for the next prime

[Green Baron]

That is cool, it looks like an iron 5, but i think in reality it comes from space.

-------------

 

Edited December 21, 2018 by Green Baron

[YNM]

[Green Baron]

A quick paint over ... see ... ready ... :-)

[cubinator]

On 12/18/2018 at 12:09 AM, qzgy said:

631!

Gap of... 12 I think. 

 

On 12/18/2018 at 6:47 PM, mabdi36 said:

673! Gap of 12 @Gargamel

I thought I warned you...  

3783289466256320478898042832094887452811366241564260711030689288561886940588046068690027219641097073851455820895101975073788224619213182637233976476211243402976039856958438443961386162515182765652796454163901930854267000117035896706603031609891821584289471477743241214582528792544026146683882033507780068309815664832001817356264972401024618769906980842018635588217705273149252035324629268922023435822415740038586023117148054448507607779407014989014665556876016341779467003092777506854851387736550050775543417770772589155258132920059467108066815287513562322535800113689788554674950277106110039999967309016391250121526069647070432631609722242128161056567286928290513876178684843814711697738835446983626882172329010122591736178865843369496728811605820828305279047545197942348909818202223658917042798916329181998681311811762067481182802705493565333806823338552940113516463945462591903169688308466200727342827799987774370433799941058287006650059685115543780857741662277910013586557439277994966285962028667946512075952673933994659057275659249429552275887741172539288080335062613667661775319721076585968747076736327671004964106568041668269695075458743434448603515090922562336594479717542686236053310821669807903972094970373323128215860285905784668084033362015299308760110495315879122021346314432618600376194822527472738824537250465427874140651520000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 is clearly divisible by 10.

As is  61249584099358401539774988285121649211647782880181065019552657036267338153088195303988201779967275642784589505913349592976251572958797164520286603082616258499126414850388770750032832244874744865500684599339365169094265281656246018624169125087086336929008659140773790287427038315506740711640971717627407262119806133914039569804387544893605360482632749642132398074143010093832414811273406748220437584361624445361171146706501836044960640727879585735220969146850637281930634576684379022439144569827759897323120413808197447743317836963898751450642251281351982277623696403714801809091137618510094637754741546381374172490209156669750628265287758243565040756752491082629092890931663069084118249960190350279925210044221389170848672643624902424798289485981643559009642358060100976306359010066013465973059932028926310180595315985960099791957394179039519432507444190747654625992620055591848528852607925564873303749001475451862943569149219508203963665660697011849205174996326078837279628237406181221912723812127044670946612175065696608648876366755523800502033220426264259724448110042998615347327090687044945724644868095726898042638404229137017574884525227292991943592508583104116919096883640157188742952660337139750108570879849335960456768856494175006057451288109527150100807278246132549650716938934121106772599000305859091685578549764454500874996178837114679306052077693402114826710945748516120895211107804543955416170463298478450007640457295281818515443548160000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

==========================

The next prime number is 947.

[Kerbart]

On 12/20/2018 at 2:51 PM, Mad Rocket Scientist said:

883

This way is a bit faster and keeps track of gaps:

import math
#import matplotlib.pyplot as plt

def isprime(number):
    if number == 1:
(...)
#plt.show()
print(max_gap)

 

Is this a challenge?

m = 10000

def isprime(n):
    return all(n % i for i in range(2, n))

primes = [i for i in range(2, m + 1) if isprime(i)]
gaps = [j - i for i, j in zip(primes, primes[1:])]
print(max(gaps))

 

Anyway, 947

Edited December 22, 2018 by Kerbart
Used "quote" instead of "code"

[Green Baron]

It wasn't meant as a challenge initially, just as a "lure" for the colleagues who asked lately "how do i start coding". Nice to see you guys biting :-)

[Xurkitree]

967