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 A325674 #9 Feb 20 2022 08:18:26
%S A325674 2,1,-1,1,-1,0,5,-20,55,-125,251,-462,803,-1364,2365,-4367,8735,
%T A325674 -18564,40409,-87380,184603,-379049,758099,-1486674,2884775,-5592404,
%U A325674 10919089,-21572459,43144919,-87087000,176565485,-357913940,723002335,-1453179125,2906358250
%N A325674 First term of n-th difference sequence of (floor(k*r)), r = sqrt(8), k >= 0.
%H A325674 Clark Kimberling, <a href="/A325674/b325674.txt">Table of n, a(n) for n = 1..199</a>
%t A325674 Table[First[Differences[Table[Floor[Sqrt[8]*n], {n, 0, 30}], n]], {n, 0, 50}]
%Y A325674 Cf. A022842, A325664, A325675.
%K A325674 easy,sign
%O A325674 1,1
%A A325674 _Clark Kimberling_, May 15 2019