A087685 Primes p such that 5^p - 4^p is composite.

2, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 47, 53, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 193, 197, 199, 211, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307

Offset

1,1

Links

Table of n, a(n) for n=1..58.

Prog

(PARI) apmb(a, b, n) = { forprime(x=2, n, y=a^x-b^x; if(!ispseudoprime(y), print1(x", "); ) ) }

Crossrefs

Cf. A005060.

Sequence in context: A173494 A137519 A045344 * A020619 A165439 A228200

Adjacent sequences: A087682 A087683 A087684 * A087686 A087687 A087688

Keyword

nonn

Author

Cino Hilliard, Oct 26 2003

Extensions

Checked by Ray Chandler, Apr 24 2007

Status

approved