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A087763 Primes p such that 8^p - 7^p is composite. 5

%I #14 Jul 19 2022 01:20:34

%S 2,3,5,13,19,23,37,41,43,47,53,59,61,67,71,73,83,89,97,101,103,107,

%T 109,127,137,149,151,157,163,167,173,179,181,191,193,197,199,211,223,

%U 227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317

%N Primes p such that 8^p - 7^p is composite.

%t Select[Prime[Range[70]],CompositeQ[8^#-7^#]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 15 2018 *)

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

%Y Cf. A016177.

%Y 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), this sequence (k=8), A087894 (k=9), A087895 (k=10).

%K nonn

%O 1,1

%A _Cino Hilliard_, Oct 26 2003

%E Offset corrected by _Mohammed Yaseen_, Jul 18 2022

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Last modified April 19 07:11 EDT 2024. Contains 371782 sequences. (Running on oeis4.)