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 A294251 #17 Dec 02 2021 11:31:02
%S A294251 1,1,3,19,97,681,5971,50443,512289,5821777,67968451,880345731,
%T A294251 12230425153,177123301369,2759869352787,45321758937211,
%U A294251 776008738668481,14020831026652833,264488668445049859,5187662544182915827,106241960755765408161,2257485400533886011721
%N A294251 E.g.f.: exp((1+x)*(1+x^2)*(1+x^3) - 1).
%H A294251 Seiichi Manyama, <a href="/A294251/b294251.txt">Table of n, a(n) for n = 0..484</a>
%F A294251 a(n) = a(n-1) + 2*(n-1)*a(n-2) + 6*(n-2)*(n-1)*a(n-3) + 4*(n-3)*(n-2)*(n-1)*a(n-4) + 5*(n-4)*(n-3)*(n-2)*(n-1)*a(n-5) + 6*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*a(n-6). - _Vaclav Kotesovec_, Dec 02 2021
%o A294251 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp((1+x)*(1+x^2)*(1+x^3)-1)))
%Y A294251 Column k=3 of A294250.
%Y A294251 Cf. A294214, A294291.
%K A294251 nonn
%O A294251 0,3
%A A294251 _Seiichi Manyama_, Oct 26 2017