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A087759
Primes p such that 7^p - 6^p is composite.
5
5, 11, 13, 17, 19, 23, 31, 37, 43, 47, 53, 59, 61, 71, 73, 79, 83, 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, 283, 293
OFFSET
1,1
MATHEMATICA
Select[Prime[Range[70]], CompositeQ[7^#-6^#]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 12 2019 *)
PROG
(PARI) apmb(a, b, n) = { forprime(x=2, n, y=a^x-b^x; if(!ispseudoprime(y), print1(x", "); ) ) }
CROSSREFS
Cf. A016169.
Primes p such that k^p - (k-1)^p is composite: A087489 (k=3), A087490 (k=4), A087685 (k=5), A087749 (k=6), this sequence (k=7), A087763 (k=8), A087894 (k=9), A087895 (k=10).
Sequence in context: A082554 A141246 A288445 * A234644 A299791 A230359
KEYWORD
nonn
AUTHOR
Cino Hilliard, Oct 26 2003
EXTENSIONS
Offset corrected by Mohammed Yaseen, Jul 18 2022
STATUS
approved