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 A053454 #12 Jan 28 2022 21:52:28 %S A053454 1,1,4,12,53,237,1306,7537,47913,322253,2297874,17191216,134505656, %T A053454 1095715055,9267223594,81162609328,734511656413,6856030049629, %U A053454 65899370570285,651338242941020,6611459646337423,68842439737228261 %N A053454 Number of weakly connected digraphs with n arcs. %H A053454 Andrew Howroyd, <a href="/A053454/b053454.txt">Table of n, a(n) for n = 0..50</a> %F A053454 Inverse Euler transform of A053418. - _Max Alekseyev_, Jan 22 2010 %o A053454 (PARI) \\ See A054733 for G, InvEulerMTS. %o A053454 seq(n)=Vec(subst(Pol(InvEulerMTS(sum(i=0, n, G(i, y+O(y^n))*x^i, O(x*x^n)))), x, 1)) \\ _Andrew Howroyd_, Jan 28 2022 %Y A053454 Column sums of A054733. %Y A053454 Row sums of A350789. %Y A053454 Cf. A003085, A053418, A350752. %K A053454 nonn %O A053454 0,3 %A A053454 _Vladeta Jovovic_, Jan 12 2000 %E A053454 Extended by _Max Alekseyev_, Jan 22 2010 %E A053454 a(0)=1 prepended by _Andrew Howroyd_, Jan 28 2022