A101610 n! * Sum[k=1..ceiling(n/2), 1/k].

1, 2, 9, 36, 220, 1320, 10500, 84000, 828576, 8285760, 97796160, 1173553920, 16145775360, 226040855040, 3554072121600, 56865153945600, 1006228442419200, 18112111963545600, 356294637348249600

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Mathematica

Table[n!Sum[1/k, {k, 1, Ceiling[n/2]}], {n, 20}]  (* Harvey P. Dale, Apr 25 2011 *)

Crossrefs

Cf. A101609, A101611, A101612, A101613, A000254, A046673, A052517.

Sequence in context: A150982 A003161 A305206 * A111601 A328268 A330346

Adjacent sequences: A101607 A101608 A101609 * A101611 A101612 A101613

Keyword

nonn,easy

Author

Ralf Stephan, Dec 10 2004

Status

approved