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.

A095971 If p(k) is the k-th prime, then the n-th set of 4 consecutive cousin prime pairs starts at p(a(n)).

Original entry on oeis.org

25, 147, 149, 1828, 1866, 18814, 20033, 26397, 57344, 63654, 71722, 72982, 76928, 85072, 99739, 110985, 122244, 136645, 145805, 166884, 183130, 204206, 244875, 246292, 256139, 258721, 258723, 263243, 296747, 296749, 299538, 336778, 356245, 396811, 425385, 449918, 455824, 467844, 478051, 494380
Offset: 1

Views

Author

Ray G. Opao, Jul 15 2004

Keywords

Examples

			a(1)=25: p(25)=97 and p(26)=101, the first cousin prime pair; p(27)=103 and p(28)=107, the second cousin prime pair; p(29)=109 and p(30)=113, the third cousin prime pair; p(31)=127 and p(32)=131, the fourth cousin prime pair.
		

Programs

  • Maple
    P:= select(isprime,[2,seq(i,i=3..10^7,2)]):
    G:= P[2..-1]-P[1..-2]:
    select(t -> G[t] =4 and G[t+2] = 4 and G[t+4] = 4 and G[t+6] = 4, [$1..nops(G)-6]); # Robert Israel, May 15 2025

Extensions

More terms from Robert Israel, May 15 2025