A101821 Triangle read by rows: T(n,h) = number of functions f:{1,2,...,n}->{1,2,...,n-2} such that |Image(f)|=h, h=1,2,...,n-2; n=3,4,....

2, 3, 42, 4, 180, 600, 5, 620, 5400, 7800, 6, 1890, 36120, 126000, 100800, 7, 5534, 202860, 1428840, 2646000, 1340640, 8, 14280, 1016400, 13053600, 46710720, 53343360, 18627840, 9, 36792, 4702320, 103133520, 642978000, 1380576960

Offset

0,1

Links

Table of n, a(n) for n=0..33.

Formula

T(n, h) = C(n-2, h)*U(n, h), where U(n, h) is the array in A019538.

Example

First rows:
2
3 42
4 180 600
5 620 5400 7800

Crossrefs

Cf. A019538, A101817, A101819.

Sequence in context: A123993 A351820 A271331 * A121475 A379922 A334533

Adjacent sequences: A101818 A101819 A101820 * A101822 A101823 A101824

Keyword

nonn,tabl

Author

Clark Kimberling, Dec 17 2004

Status

approved