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A054592 Number of disconnected labeled graphs with n nodes. 13
0, 1, 4, 26, 296, 6064, 230896, 16886864, 2423185664, 687883494016, 387139470010624, 432380088071584256, 959252253993204724736, 4231267540316814507357184, 37138269572860613284747227136 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n)=2^binomial(n,2)-A001187(n)

LINKS

Table of n, a(n) for n=1..15.

MATHEMATICA

g=Sum[2^Binomial[n, 2]x^n/n!, {n, 0, 20}]; Range[0, 20]! CoefficientList[Series[g-Log[g]-1, {x, 0, 20}], x]  (* Geoffrey Critzer, Nov 11 2011 *)

CROSSREFS

Cf. A000719.

Sequence in context: A304864 A167811 A156306 * A102202 A271613 A271614

Adjacent sequences:  A054589 A054590 A054591 * A054593 A054594 A054595

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Apr 15 2000

STATUS

approved

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Last modified August 5 00:15 EDT 2021. Contains 346456 sequences. (Running on oeis4.)