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 A344400 #10 May 24 2021 07:37:49 %S A344400 6,102,1008,7860,53340,330372,1918224,10615176,56602260,293032740, %T A344400 1481004096,7337198232,35743534008,171641101800,814046047200, %U A344400 3819148459920,17747499595140,81776562767460,373968175442400,1698587342436600,7667851012141320,34422129328312440 %N A344400 a(n) = [x^n] 6*(8*x^3 + 3*x + 1) / (1 - 4*x)^(7/2). %C A344400 The sequence and its sister sequence A344401 are related to Frédéric Chapoton's sequences A344228 and A344321, as described in the linked remark. %H A344400 Peter Luschny, <a href="/A344400/a344400.pdf">Remark regarding A344228 and A344321</a>. %F A344400 a(n) = A344228(n+1)*(n+1)*(n+2). - _John Keith_, May 23 2021 %p A344400 aList := proc(len) local gf, ser; %p A344400 gf := 6*(8*x^3 + 3*x + 1) / (1 - 4*x)^(7/2): %p A344400 ser := series(gf, x, len+2): seq(coeff(ser, x, n), n = 0..len) end: %p A344400 aList(21); %Y A344400 Cf. A344401, A344228, A344321. %K A344400 nonn %O A344400 0,1 %A A344400 _Peter Luschny_, May 16 2021