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A339040 Number of unlabeled connected simple graphs with n edges rooted at two noninterchangeable vertices. 6
1, 3, 10, 35, 125, 460, 1747, 6830, 27502, 113987, 485971, 2129956, 9591009, 44341610, 210345962, 1023182861, 5100235807, 26035673051, 136023990102, 726877123975, 3970461069738, 22156281667277, 126234185382902, 733899631974167, 4351500789211840 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..25.

FORMULA

G.f.: f(x)/g(x) - r(x)^2 where f(x), g(x) and r(x) are the g.f.'s of A339063, A000664 and A339039.

PROG

(PARI) \\ See A339063 for G.

seq(n)={my(A=O(x*x^n), g=G(2*n, x+A, [])); Vec(G(2*n, x+A, [1, 1])/g - (G(2*n, x+A, [1])/g)^2)}

CROSSREFS

Cf. A000664, A002905, A303832, A304074, A339039, A339041, A339042, A339044, A339063.

Sequence in context: A224509 A026026 A047037 * A201058 A318113 A216710

Adjacent sequences:  A339037 A339038 A339039 * A339041 A339042 A339043

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Nov 20 2020

STATUS

approved

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Last modified April 12 03:14 EDT 2021. Contains 342912 sequences. (Running on oeis4.)