A215865 Number of simple labeled graphs on n+5 nodes with exactly n connected components that are trees or cycles.

0, 1356, 15029, 90734, 394506, 1381695, 4138827, 11002068, 26603148, 59546487, 124984860, 248436188, 471271892, 858408642, 1508851218, 2569865520, 4255708464, 6872006526, 10847057991, 16771536474, 25448295950, 37954221305, 55716334245, 80604653220

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Formula

G.f.: (194*x^4-713*x^3-5*x^2+113*x+1356)*x/(1-x)^11.

a(n) = C(n+5,6)*(3*n^4+130*n^3+1565*n^2+7006*n+12992)/16.

Maple

a:= n-> binomial(n+5, 6)*(12992+(7006+(1565+(130+3*n)*n)*n)*n)/16:
seq(a(n), n=0..40);

Crossrefs

A diagonal of A215861.

Sequence in context: A107559 A056103 A259249 * A172379 A192319 A125270

Adjacent sequences: A215862 A215863 A215864 * A215866 A215867 A215868

Keyword

nonn

Author

Alois P. Heinz, Aug 25 2012

Status

approved