The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #5 Nov 15 2024 19:38:55
%S 1,0,1,2,3,6,16,37,100,293,888,2822,9305,31274,106972,370828,1298058,
%T 4582413,16289759,58259600,209465186
%N Number of embeddings on the sphere of 2-connected homeomorphically irreducible planar graphs with n edges.
%C Homeomorphically irreducible means each vertex has a degree of at least 3.
%F a(n) = A002840(n) + A187928(n).
%F a(n) = Sum_{k=4..n-2} A378075(k, n+2-k).
%Y Antidiagonal sums of A378075.
%Y Cf. A002840, A006407, A187928.
%K nonn,more
%O 6,4
%A _Andrew Howroyd_, Nov 15 2024