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A127123 Triangle read by rows: T(n,k) = number of endofunctions on n points with k points in the image. 0
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 (list; table; graph; refs; listen; history; text; internal format)
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 A103525

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

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Last modified July 11 08:10 EDT 2020. Contains 335626 sequences. (Running on oeis4.)