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A339044 Number of unlabeled connected simple graphs with n edges rooted at one oriented edge. 5
1, 2, 6, 18, 57, 188, 651, 2336, 8719, 33741, 135185, 559908, 2394326, 10557283, 47943126, 223987316, 1075455181, 5301593544, 26807904317, 138924912857, 737220195148, 4002876571636, 22221898966507, 126042573704637, 729944250603862, 4313430995825272 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..26.

FORMULA

G.f.: x*f(x)/((1+x)*g(x)) where f(x) is the g.f. of A339063 and g(x) is the g.f. of A000664.

PROG

(PARI) \\ See A339063 for G.

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

CROSSREFS

Cf. A000664, A002905, A303832, A304072, A339037, A339039, A339040, A339041, A339063.

Sequence in context: A104629 A000957 A307496 * A125305 A273203 A148458

Adjacent sequences:  A339041 A339042 A339043 * A339045 A339046 A339047

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Nov 21 2020

STATUS

approved

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Last modified April 13 02:22 EDT 2021. Contains 342934 sequences. (Running on oeis4.)