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 A159234 #19 Apr 03 2023 10:36:11
%S A159234 27,807,1707,2977,3027,3277,4717,5137,5677,5917,5967,6187,7087,7357,
%T A159234 7597,7707,8217,9117,9297,9387,9667,9877,9927,9997,10387,11097,11647,
%U A159234 11797,12727,13407,13867,15757,15987,16327,16507,16857,17347,17767,18237,18817,18997
%N A159234 Composite numbers n such that 8*n^2-2*n-1 divides the primitive part U(n) of Fibonacci(n).
%H A159234 Chris Caldwell, The Prime Glossary, <a href="https://t5k.org/glossary/xpage/FibonacciNumber.html">Fibonacci number</a>
%t A159234 lst = {1}; Do[f = Fibonacci[a]; Do[f = f/GCD[f, lst[[d]]], {d, Most[Divisors[a]]}]; AppendTo[lst, f], {a, 2, 19000}]; Flatten[Table[If[! PrimeQ[n] && Mod[lst[[n]], 8*n^2 - 2*n - 1] == 0, n, {}], {n, 19000}]] (* _Arkadiusz Wesolowski_, Dec 12 2011 *)
%Y A159234 Subsequence of A159259.
%Y A159234 Cf. A000045, A023172, A061446, A159231, A181890.
%K A159234 nonn
%O A159234 1,1
%A A159234 _Arkadiusz Wesolowski_, Apr 06 2009