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 A035512 #27 Feb 16 2025 08:32:37 %S A035512 1,1,1,5,83,5048,1047008,705422362,1580348371788,12139024825260556, %T A035512 328160951349343885604,31831080872412589394328804, %U A035512 11234274997368899732057135454531,14576252633139820879894296847900227082 %N A035512 Number of unlabeled strongly connected digraphs with n nodes. %D A035512 F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 218. %D A035512 V. A. Liskovets, A contribution to the enumeration of strongly connected digraphs, Dokl. AN BSSR, 17 (1973), 1077-1080, MR49#4849. %D A035512 R. C. Read and R. J. Wilson, An Atlas of Graphs, Oxford, 1998. %D A035512 R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1976. %H A035512 Andrew Howroyd, <a href="/A035512/b035512.txt">Table of n, a(n) for n = 0..50</a> (terms 0..18 from R. W. Robinson) %H A035512 A. M. Hinz, S. Klavžar, U. Milutinović, C. Petr, <a href="http://dx.doi.org/10.1007/978-3-0348-0237-6">The Tower of Hanoi - Myths and Maths</a>, Birkhäuser 2013. See page 251. <a href="http://tohbook.info">Book's website</a> %H A035512 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/StronglyConnectedDigraph.html">Strongly Connected Digraph.</a> %o A035512 (PARI) \\ See PARI link in A350489 for program code. %o A035512 A035512seq(15) \\ _Andrew Howroyd_, Jan 13 2022 %Y A035512 The labeled version is A003030. %Y A035512 Row sums of A057276. %Y A035512 Column sums of A350753. %Y A035512 Cf. A003085, A049387, A350489, A350752. %K A035512 nonn,nice %O A035512 0,4 %A A035512 Ronald C. Read %E A035512 a(12) and a(13) added by _N. J. A. Sloane_ from the Robinson report, Oct 17 2006