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 A239926 #58 Sep 08 2022 08:46:07
%S A239926 17,473,54953,515057,42784577,386371913,31364282393,22875718713137,
%T A239926 205886837127353,150094360419092177,12157661061010417697,
%U A239926 109418971539326314793,8862937838177524385273,6461081871212274789450257,4710128696093323330314756713
%N A239926 3^(p-1)-2^(p+1) for primes p > 3.
%C A239926 3^(p-1)-2^(p+1) can be written as (3^((p-1)/2)-2^((p+1)/2))*(3^((p-1)/2)+2^((p+1)/2)). Since 3^((p-1)/2)-2^((p+1)/2) > 1 for p > 5, these numbers are all composite after 17 = (3^2-2^3)*(3^2+2^3).
%H A239926 Vincenzo Librandi, <a href="/A239926/b239926.txt">Table of n, a(n) for n = 1..200</a>
%t A239926 Table[3^(Prime[n] - 1) - 2^(Prime[n] + 1), {n, 3, 100}]
%o A239926 (Magma) [3^(p-1)-2^(p+1): p in PrimesInInterval(4,100)];
%Y A239926 Cf. A000040, A003063, A135171 (numbers of the form 3^p-2^p with p prime), A214091 (supersequence).
%K A239926 nonn,easy,less
%O A239926 1,1
%A A239926 _Vincenzo Librandi_, Jun 17 2014