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

Author

Ralf Stephan, Dec 10 2004

Keywords

• nonn
• easy

Crossrefs

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

Programs

Mathematica

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