Sexy Prime Generator
| // A short prime tester: | |
| // t(11) -> true | |
| // t(12) -> false | |
| function t( | |
| n, //Input | |
| i //Placeholder | |
| ){ | |
| for(i=2;i<n;i++) | |
| if(!(n%i)) | |
| return!1; | |
| return!0 | |
| } | |
| // Sexy prime generator | |
| // https://en.wikipedia.org/wiki/Sexy_prime | |
| function s( | |
| n, //Input | |
| p //Placeholder | |
| ){ | |
| // Loop through all numbers from 2 till n-6, checking primacy of i and i+6 | |
| for( | |
| p=[], //Initialize array | |
| i=2; | |
| i<n-6; | |
| i++ | |
| ) | |
| // If both i and i+6 are prime, add to p | |
| if(t(i)&&t(i+6)) | |
| p.push([i,i+6]); | |
| return p | |
| } |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2012 Inkbug | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. |
| { | |
| "name": "SexyPrimes", | |
| "description": "A Sexy Prime generator, plus a prime checker.", | |
| "keywords": [ | |
| "prime", | |
| "generator" | |
| ] | |
| } |
| <!DOCTYPE html> | |
| <title>Sexy Primes</title> | |
| <div>Expected value: <b>[[5,11],[7,13]]</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| // write a small example that shows off the API for your example | |
| // and tests it in one fell swoop. | |
| function t(n,i){for(i=2;i<n;i++)if(!(n%i))return!1;return!0}function s(n,p){for(p=[],i=2;i<n-6;i++)if(t(i)&&t(i+6))p.push([i,i+6]);return p} | |
| document.getElementById( "ret" ).innerHTML = s(15) | |
| </script> |
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Just simply combine two functions:
function f(a,b,c,d,e){for(d=c=[];b?b%--a:d++<a-6;)b||f(d,d)|f(e=d+6,e)||c.push([d,e]);return b?a^1:c}