cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A152091 Primes which are the sum of cousin prime pairs + 1.

Original entry on oeis.org

11, 19, 31, 43, 79, 139, 163, 199, 211, 223, 331, 463, 619, 631, 883, 919, 1231, 1291, 1483, 1543, 1723, 1759, 1879, 2179, 2851, 2971, 3163, 3331, 3391, 3571, 3739, 4003, 4483, 4591, 4759, 4783, 4951, 5323, 5419, 5503, 6043, 6079, 6163, 6379, 6691, 7351
Offset: 2

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Author

Cino Hilliard, Nov 24 2008

Keywords

Comments

3 and 7 are the only cousin primes with another prime (5) between them. - Harvey P. Dale, Jul 28 2012

Examples

			prime(2)=3, 3 + 4 = 7, 3 + 7 + 1 = 11, the first term in the sequence.
		

Programs

  • Mathematica
    Join[{11},Select[Total/@Select[Partition[Prime[Range[600]],2,1], Last[#]-First[#]==4&]+1,PrimeQ]] (* Harvey P. Dale, Jul 28 2012 *)
  • PARI
    g4(n) = for(x=2,n,p=prime(x);if(isprime(p+4),y=p+p+4+1;if(isprime(y), print1(y","))))
    
  • PARI
    isA152091(n) = if(n%2==0,0,isprime(n) && isprime((n-5)/2) && isprime((n+3)/2)) \\ Michael B. Porter, Mar 17 2010

Formula

Cousin primes are prime pairs that differ by 4.