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 A325736 #4 Jun 03 2019 19:47:39
%S A325736 5,0,1,-3,7,-15,31,-63,126,-245,455,-791,1253,-1715,1715,0,-6419,
%T A325736 24157,-67081,162925,-364609,767977,-1535953,2922679,-5273325,8931521,
%U A325736 -13886641,18775981,-18399241,-2035799,79594559,-300540195,855744647,-2151510735,5025003039
%N A325736 First term of n-th difference sequence of (floor(2e*k)), k >= 0.
%H A325736 Clark Kimberling, <a href="/A325736/b325736.txt">Table of n, a(n) for n = 1..200</a>
%t A325736 Table[First[Differences[Table[Floor[2E*n], {n, 0, 50}], n]], {n, 1, 50}]
%Y A325736 Cf. A325664.
%K A325736 easy,sign
%O A325736 1,1
%A A325736 _Clark Kimberling_, May 23 2019