This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A087490 #19 Mar 14 2025 14:43:43
%S A087490 5,11,13,19,23,29,31,37,41,43,47,53,61,67,71,73,79,83,89,97,101,103,
%T A087490 107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,
%U A087490 197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,293,307
%N A087490 Primes p such that 4^p - 3^p is composite.
%C A087490 Primes not in A059801. - _Robert Israel_, Nov 03 2024
%H A087490 Robert Israel, <a href="/A087490/b087490.txt">Table of n, a(n) for n = 1..10000</a>
%p A087490 filter:= p -> isprime(p) and not isprime(4^p-3^p):
%p A087490 select(filter, [seq(i,i=3..1000,2)]); # _Robert Israel_, Nov 03 2024
%t A087490 Select[Prime[Range[70]],CompositeQ[4^#-3^#]&] (* _Harvey P. Dale_, Mar 14 2025 *)
%o A087490 (PARI) apmb(a,b,n) = { forprime(x=2,n, y=a^x-b^x; if(!ispseudoprime(y), print1(x","); ) ) }
%Y A087490 Cf. A005061, A059801.
%Y A087490 Primes p such that k^p - (k-1)^p is composite: A087489 (k=3), this sequence (k=4), A087685 (k=5), A087749 (k=6), A087759 (k=7), A087763 (k=8), A087894 (k=9), A087895 (k=10).
%K A087490 nonn
%O A087490 1,1
%A A087490 _Cino Hilliard_, Oct 26 2003
%E A087490 Offset corrected by _Mohammed Yaseen_, Jul 18 2022