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 A378076 #5 Nov 15 2024 19:38:55
%S A378076 1,0,1,2,3,6,16,37,100,293,888,2822,9305,31274,106972,370828,1298058,
%T A378076 4582413,16289759,58259600,209465186
%N A378076 Number of embeddings on the sphere of 2-connected homeomorphically irreducible planar graphs with n edges.
%C A378076 Homeomorphically irreducible means each vertex has a degree of at least 3.
%F A378076 a(n) = A002840(n) + A187928(n).
%F A378076 a(n) = Sum_{k=4..n-2} A378075(k, n+2-k).
%Y A378076 Antidiagonal sums of A378075.
%Y A378076 Cf. A002840, A006407, A187928.
%K A378076 nonn,more
%O A378076 6,4
%A A378076 _Andrew Howroyd_, Nov 15 2024