A127123 Triangle read by rows: T(n,k) = number of endofunctions on n points with k points in the image.

1, 1, 2, 1, 3, 3, 1, 6, 7, 5, 1, 7, 18, 14, 7, 1, 10, 33, 49, 26, 11, 1, 11, 52, 110, 109, 45, 15, 1, 14, 75, 221, 314, 229, 75, 22, 1, 15, 105, 372, 746, 788, 438, 120, 30, 1, 18, 136, 601, 1508, 2222, 1797, 806, 187, 42, 1, 19, 174, 888, 2763, 5208, 5888, 3806, 1404, 284, 56

Offset

1,3

Links

Table of n, a(n) for n=1..66.

Example

For n = 3, the 7 endofunctions are (1,2,3) -> (1,1,1), (1,1,2), (1,2,1), (2,1,1), (1,2,3), (1,3,2) and (2,3,1). The number of points in the image are respectively 1,2,2,2,3,3,3, so row 3 is 1,3,3.
The triangle starts:
1
1 2
1 3 3
1 6 7 5
1 7 18 14 7

Crossrefs

Sequence in context: A262917 A165007 A284979 * A271238 A186740 A353585

Adjacent sequences: A127120 A127121 A127122 * A127124 A127125 A127126

Keyword

nonn,tabl

Author

Franklin T. Adams-Watters, with additional values from Christian Bower, Jan 05 2007

Status

approved