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 A350906 #6 Jan 22 2022 18:28:11 %S A350906 1,1,2,5,16,56,241,1111,5748,31912,190328,1204317,8050341,56516303, %T A350906 415128256,3179020729,25308005049,208918893640,1784451646305, %U A350906 15739926014382,143130061546156,1339761466105929,12891329514544223,127351374611721837,1290198076415425548,13390893744153374776 %N A350906 Number of unlabeled initially-finally connected digraphs with n arcs. %o A350906 (PARI) A350906seq(15) \\ See PARI link in A350794 for program code. %Y A350906 Column sums of A057278. %Y A350906 Cf. A049531 (by vertices), A350752, A350796, A350798, A350907. %K A350906 nonn %O A350906 0,3 %A A350906 _Andrew Howroyd_, Jan 21 2022