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A378076
Number of embeddings on the sphere of 2-connected homeomorphically irreducible planar graphs with n edges.
3
1, 0, 1, 2, 3, 6, 16, 37, 100, 293, 888, 2822, 9305, 31274, 106972, 370828, 1298058, 4582413, 16289759, 58259600, 209465186
OFFSET
6,4
COMMENTS
Homeomorphically irreducible means each vertex has a degree of at least 3.
FORMULA
a(n) = A002840(n) + A187928(n).
a(n) = Sum_{k=4..n-2} A378075(k, n+2-k).
CROSSREFS
Antidiagonal sums of A378075.
Sequence in context: A126317 A079437 A061220 * A184322 A159340 A369560
KEYWORD
nonn,more
AUTHOR
Andrew Howroyd, Nov 15 2024
STATUS
approved