A121564 Denominator of Sum[i=1..n] i!/(i^i).

1, 2, 18, 288, 180000, 1620000, 190591380000, 780662292480000, 46097327708651520000, 28810829817907200000000, 747278726094210559615027200000000, 747278726094210559615027200000000

Offset

1,2

Comments

Numerators are A121563. Limit as n approaches infinity of A121563(n)/A121564(n) = 1.879853862175258533486306145... whose decimal expansion is A094082.

Links

Table of n, a(n) for n=1..12.

Formula

Denominator of Sum[i=1..n] i!/(i^i) A000142(i)/A000312(i).

Example

a(1) = 1/1 = 1.
a(2) = 3/2 = 1.5
a(3) = 31/18 = 1.72222222222.
a(4) = 523/288 = 1.81597222222.
a(5) = 333787/180000 = 1.85437222222.

Crossrefs

Cf. A000142, A000312, A055775, A094082.

Sequence in context: A131455 A084947 A123385 * A224384 A092563 A258922

Adjacent sequences: A121561 A121562 A121563 * A121565 A121566 A121567

Keyword

easy,frac,nonn

Author

Jonathan Vos Post, Aug 07 2006

Status

approved