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 A054053 #24 Mar 08 2021 22:50:27
%S A054053 4,126,7336,665120,80038860,11992785628,2148752458832,448000621008112,
%T A054053 106551292402319492,28471977293653977714,8445425847422222518488,
%U A054053 2753705028193531309816184,978990839708922602845440908,376905974468378563863272876248,156221832236610857130449469228920,69360325968752963320307268181976608
%N A054053 Number of nonisomorphic connected n-state automata with binary inputs and outputs.
%C A054053 Inverse Euler transform of A054052.
%D A054053 F. Harary and E. Palmer, Graphical Enumeration, 1973. [See Section 6.5, pp. 146-150.]
%H A054053 Christian G. Bower, <a href="https://oeis.org/transforms_pari.txt">PARI programs for transforms</a>, 2007.
%H A054053 Michael A. Harrison, <a href="http://dx.doi.org/10.4153/CJM-1965-010-9">A census of finite automata</a>, Canad. J. Math., 17, No. 1 (1965), 100-113. [See Table III, p. 112.]
%H A054053 N. J. A. Sloane, <a href="/transforms.txt">Maple program for transforms</a>, 2001-2020.
%o A054053 (PARI) /* This program is a modification of _Christian G. Bower_'s PARI program for the inverse Euler transform from the link above. */
%o A054053 lista(nn) = {local(A=vector(nn+1)); for(n=1, nn+1, A[n]=if(n==1, 1, A054052(n-1))); local(B=vector(#A-1, n, 1/n), C); A[1] = 1; C = log(Ser(A)); A=vecextract(A, "2.."); for(i=1, #A, A[i] = polcoeff(C, i)); A = dirdiv(A, B); } \\ _Petros Hadjicostas_, Mar 08 2021
%Y A054053 Cf. A000282, A054052, A054742.
%K A054053 nonn
%O A054053 1,1
%A A054053 _Vladeta Jovovic_, Apr 29 2000
%E A054053 Terms a(14)-a(16) from _Petros Hadjicostas_, Mar 08 2021