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 A325666 #14 Feb 20 2022 07:50:33
%S A325666 1,1,-1,0,3,-9,19,-35,63,-119,239,-495,1023,-2079,4158,-8239,16247,
%T A325666 -31823,61402,-115291,207669,-352715,550429,-748143,748143,1,-2848367,
%U A325666 10897033,-30955333,77558760,-181129041,404458737,-875889377,1855921144,-3870685665
%N A325666 First term of n-th difference sequence of (floor(k*r)), r = sqrt(3), k >= 0.
%H A325666 Clark Kimberling, <a href="/A325666/b325666.txt">Table of n, a(n) for n = 1..200</a>
%t A325666 Table[First[Differences[Table[Floor[Sqrt[3]*n], {n, 0, 50}], n]], {n, 1, 50}]
%Y A325666 Cf. A325664, A325667.
%K A325666 easy,sign
%O A325666 1,5
%A A325666 _Clark Kimberling_, May 13 2019