A087894 Primes p such that 9^p - 8^p is composite.

3, 5, 11, 13, 17, 19, 23, 37, 41, 43, 47, 53, 59, 61, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 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, 283, 293, 307

Offset

1,1

Links

Table of n, a(n) for n=1..57.

Mathematica

Select[Prime[Range[100]], !PrimeQ[9^#-8^#]&] (* Harvey P. Dale, May 01 2011 *)

Prog

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

Crossrefs

Cf. A016185.

Primes p such that k^p - (k-1)^p is composite: A087489 (k=3), A087490 (k=4), A087685 (k=5), A087749 (k=6), A087759 (k=7), A087763 (k=8), this sequence (k=9), A087895 (k=10).

Sequence in context: A020620 A136056 A059636 * A245048 A338018 A059352

Adjacent sequences: A087891 A087892 A087893 * A087895 A087896 A087897

Keyword

nonn

Author

Cino Hilliard, Oct 26 2003

Extensions

Offset corrected by Mohammed Yaseen, Jul 19 2022

Status

approved