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 A145099 #11 Mar 12 2020 05:26:48
%S A145099 1,1,0,1,1,0,0,0,1,1,0,0,0,1,1,1,1,1,0,1,1,1,1,0,0,0,1,0,0,0,0,0,1,1,
%T A145099 0,0,1,0,0,0,1,0,0,0,1,1,0,1,0,1,0,0,0,0,0,0,1,0,0,0,0,1,1,0,0,0,0,0,
%U A145099 0,1,0,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0
%N A145099 a(n) = 1 if the largest proper divisor of Mersenne composite A145097(n) is prime and a(n) = 0 in opposite case.
%H A145099 Amiram Eldar, <a href="/A145099/b145099.txt">Table of n, a(n) for n = 1..191</a>
%t A145099 a = {}; Do[m = 2^Prime[n] - 1; k = Divisors[m][[ -2]]; If[PrimeQ[m], null, If[PrimeQ[k], AppendTo[a, 1], AppendTo[a, 0]]], {n, 1, 50}]; a
%Y A145099 Cf. A065341, A135975, A135980, A145097, A136031.
%K A145099 nonn
%O A145099 1,1
%A A145099 _Artur Jasinski_, Oct 01 2008
%E A145099 Name clarified and more terms added by _Amiram Eldar_, Mar 12 2020