A127436 Primes associated with A127435.

2, 5, 17, 37, 101, 257, 1297, 1601, 4357, 15877, 16901, 22501, 24337, 32401, 44101, 57601, 62501, 65537, 72901, 78401, 93637, 156817, 160001, 176401, 184901, 217157, 240101, 309137, 324901, 331777, 417317, 476101, 490001, 562501, 577601, 682277

Offset: 1

Author

Lekraj Beedassy, Jan 14 2007

Keywords

• nonn

Comments

A sequence with P=a(k) distinct numbers contains a subsequence of p=A127435(k) monotonically increasing or decreasing terms, according to a corollary of the Erdos-Szekeres theorem.

Crossrefs

Cf. A127435. Subsequence of A045349.

Programs

Mathematica

Select[(Prime@Range[300] - 1)^2 + 1, PrimeQ] (* Ray Chandler, Jan 23 2007 *)

PARI

listp(nn) = {forprime(p=2, nn, if (isprime(q=(p-1)^2 + 1), print1(q, ", ")););} \\ Michel Marcus, Jun 08 2016

Formula

a(n) = (A127435(n)-1)^2 + 1.

Extensions

Corrected and extended by Ray Chandler, Jan 23 2007