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 A006412 Number of nonseparable tree-rooted planar maps with n + 3 edges and 4 vertices. (Formerly M3697) 4
 4, 75, 604, 3150, 12480, 40788, 115500, 292578, 677820, 1459315, 2954952, 5679700, 10438272, 18449760, 31511880, 52213596, 84206100, 132543411, 204105220, 308116050, 456776320, 666022500, 956435220, 1354315950, 1892954700, 2614113099, 3569749200, 4824012424 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Andrew Howroyd, Table of n, a(n) for n = 1..1000 T. R. S. Walsh and A. B. Lehman, Counting rooted maps by genus. III: Nonseparable maps, J. Combinatorial Theory Ser. B 18 (1975), 222-259. FORMULA a(n) = 4 * binomial(n + 4, 5) + 51 * binomial(n + 4, 6) + 163 * binomial(n + 4, 7) + 194 * binomial(n + 4, 8) + 78 * binomial(n + 4, 9). - Sean A. Irvine, Apr 03 2017 a(n) = binomial(n+5,6)*(n + 3)*(13*n^2 + 57*n + 14)/84. - Andrew Howroyd, Apr 05 2021 PROG (PARI) a(n) = {binomial(n+5, 6)*(n + 3)*(13*n^2 + 57*n + 14)/84} \\ Andrew Howroyd, Apr 05 2021 CROSSREFS Column 4 of A342984. Cf. A006411, A006413. Sequence in context: A280889 A257367 A072373 * A206456 A137220 A006236 Adjacent sequences:  A006409 A006410 A006411 * A006413 A006414 A006415 KEYWORD nonn AUTHOR EXTENSIONS Terms a(11) and beyond from Andrew Howroyd, Apr 05 2021 STATUS approved

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Last modified May 5 17:26 EDT 2021. Contains 343572 sequences. (Running on oeis4.)