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 A325672 #9 Feb 20 2022 08:17:34
%S A325672 2,1,-2,4,-7,10,-10,1,26,-80,161,-242,242,1,-730,2188,-4376,6580,
%T A325672 -6733,1140,13718,-32945,18920,158356,-851599,2896920,-8097220,
%U A325672 20058301,-45540944,96506230,-193012459,367077448,-667617643,1166803110,-1968991970,3225375253
%N A325672 First term of n-th difference sequence of (floor(k*r)), r = sqrt(7), k >= 0.
%H A325672 Clark Kimberling, <a href="/A325672/b325672.txt">Table of n, a(n) for n = 1..200</a>
%t A325672 Table[First[Differences[Table[Floor[Sqrt[7]*n], {n, 0, 30}], n]], {n, 0, 50}]
%Y A325672 Cf. A022841, A325664, A325673.
%K A325672 easy,sign
%O A325672 1,1
%A A325672 _Clark Kimberling_, May 15 2019