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 A107041 #14 Feb 25 2024 01:44:32
%S A107041 1,1,2,1,3,1,1,2,4,1,1,3,1,2,1,1,2,2,2,1,3,1,1,2,2,3,1,3,1,2,1,1,2,1,
%T A107041 1,2,1,3,1,1,2,2,2,1,4,1,2,1,1,2,1,1,2,4,1,1,2,2,2,1,1,3,1,2,1,1,2,1,
%U A107041 1,2,1,3,1,1,2,2,2,1,1,3,3,1,1,2,1,1,3
%N A107041 First differences of indices of squarefree Pell numbers.
%H A107041 Amiram Eldar, <a href="/A107041/b107041.txt">Table of n, a(n) for n = 1..373</a>
%F A107041 a(n) = A107040(n+1)-A107040(n). - _R. J. Mathar_, Jan 04 2017
%t A107041 Rest[Differences[Flatten[Position[LinearRecurrence[{2,1},{1,2},100],_?SquareFreeQ]]]] (* _Harvey P. Dale_, May 30 2019 *)
%Y A107041 Cf. A000129, A005117, A107038, A107039, A107040.
%K A107041 nonn
%O A107041 1,3
%A A107041 _Paul Barry_, May 09 2005
%E A107041 More terms from _Amiram Eldar_, Feb 25 2024