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 A380364 #6 Jan 28 2025 15:28:56
%S A380364 1,1,4,30,284,3240,43282,662760,11446844,220193310,4669558564,
%T A380364 108251161920,2723857695362,73941952968000,2154117314613604,
%U A380364 67038931862069790,2219781607638887804,77922680046440538600,2890682855602209593362,112998995448368143038120,4642614436461699746566364
%N A380364 Number of rooted combinatorial maps with n edges and without faces of degree 1.
%H A380364 Andrew Howroyd, <a href="/A380364/b380364.txt">Table of n, a(n) for n = 0..200</a>
%o A380364 (PARI) seq(n)={my(A=O(x^(2*n+1)), g=serconvol(exp(x^2/2 + A),exp(-x + A)/(1-x))); Vec(substpol(1 + x*deriv(log(serlaplace(g))), x^2, x))}
%Y A380364 Cf. A379433 (planar), A380365 (sensed), A380366 (unsensed).
%Y A380364 Cf. A000166, A123023.
%K A380364 nonn
%O A380364 0,3
%A A380364 _Andrew Howroyd_, Jan 28 2025