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  1. // stackoverflow.com/a/69345662/849891
  2. //   by stackoverflow.com/users/849891/will-ness
  3.  
  4. function *primesFrom(start) {
  5. 	console.log("Starting....");
  6.     if (start <= 2) { yield 2; }
  7.     if (start <= 3) { yield 3; }
  8.     if (start <= 5) { yield 5; }
  9.     if (start <= 7) { yield 7; }
  10.     const sieve = new Map();
  11.     const ps = primesFrom(2);
  12.     ps.next();                 // skip the 2
  13.     let p = ps.next().value;   // p==3
  14.     let psqr = p * p;          // 9
  15.     let c = psqr;              // first candidate, 9
  16.     let s = 6;                 // step
  17.     let m = 9;                 // multiple
  18.     while( psqr < start )
  19.     {
  20.     	// must adjust initial state
  21.          s = 2 * p;
  22.          m = p + s * Math. ceil( (start-p)/s );
  23.          while (sieve.has(m)) m += s;
  24.          sieve.set(m, s);
  25.          p = ps.next().value;
  26.          psqr = p * p;
  27.     }
  28.     if ( start > c) { c = start; }
  29.     if ( c%2 === 0 ) { c += 1; }
  30.  
  31.     // main loop
  32.     for ( ;  true ;  c += 2 ) 
  33.     {
  34.         s = sieve.get(c);
  35.         if (s !== undefined) {
  36.             sieve.delete(c);
  37.         } else if (c < psqr) {
  38.             yield c;
  39.             continue;
  40.         } else {          // c == psqr
  41.             s = 2 * p;
  42.             p = ps.next().value;
  43.             psqr = p * p;
  44.         }
  45.         m = c + s;
  46.         while (sieve.has(m)) m += s;
  47.         sieve.set(m, s);
  48.     }
  49. }
  50.  
  51.  
  52. (function test() {
  53. 	maxItems = 50;
  54. 	from = 500000000;
  55.     const ps = primesFrom( from );
  56.     array = [];
  57.     for( i = 0; i < maxItems; i=i+1)
  58.     {
  59.     	p = ps.next().value;
  60.     	// console.log(p);
  61.         array.push( p-from );
  62.     }
  63.     console.log(array.join(','));
  64. })();
  65.  
Success #stdin #stdout 0.04s 19728KB
comments ()
stdin
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Standard input is empty
stdout
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Starting....
Starting....
Starting....
Starting....
Starting....
3,9,41,57,69,71,77,89,93,99,101,117,183,201,227,231,233,261,273,299,317,321,323,353,359,377,387,393,437,443,461,467,483,489,491,507,539,551,587,597,623,659,663,671,681,693,701,723,729,737
https://ideone.com/kyOnzT
stackoverflow.com/a/69345662/849891
language:
JavaScript (SMonkey 60.2.3)
created:
3 years ago
visibility:
secret

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