A087749 Primes p such that 6^p - 5^p is composite.

3, 7, 17, 19, 29, 31, 37, 41, 43, 47, 53, 59, 67, 71, 73, 79, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281

Offset

1,1

Links

Table of n, a(n) for n=1..53.

Mathematica

Select[Prime[Range[60]], !PrimeQ[6^#-5^#]&] (* Harvey P. Dale, Apr 26 2011 *)

Prog

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

Crossrefs

Cf. A005062.

Sequence in context: A058887 A355656 A306355 * A140863 A076194 A167168

Adjacent sequences: A087746 A087747 A087748 * A087750 A087751 A087752

Keyword

nonn

Author

Cino Hilliard, Oct 26 2003

Extensions

Corrected by Andrew S. Plewe, Apr 24 2007 (all the terms were wrong)

Checked by Ray Chandler, Apr 25 2007

Status

approved