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 A067303 #11 Dec 11 2019 21:46:20 %S A067303 1,18,1752,282304,54547200,11478167040,2533556365312,576271774875648, %T A067303 133776598692003840,31513560479297044480,7505638177922587557888, %U A067303 1802924878727702252617728,436026430783762289982963712 %N A067303 Even-indexed members of A067302. %F A067303 a(n) = A067302(2n) = (n+1)*A067297(2*n). %F A067303 G.f.: (x*(d/dx)A(x) + A(x)) with A(x) g.f. of A067320. %Y A067303 Cf. A067322 (odd-indexed members of A067302). %K A067303 nonn,easy %O A067303 0,2 %A A067303 _Wolfdieter Lang_, Feb 05 2002