A215720 - cp's OEIS frontend

A215720 The number of functions f:{1,2,...,n}->{1,2,...,n}, endofunctions, such that exactly one nonrecurrent element is mapped into each recurrent element.

n	a(n)
0	1
1	0
2	2
3	6
4	60
5	560
6	7350
7	111552
8	2009672
9	41378976
10	963527850
11	25009038560
12	716437784172
13	22453784964624
14	764345507271710
15	28085186967504240
16	1107971902218683280
17	46710909213378892352
18	2095883952368863510098
19	99724281567446320231104
20	5015524096516005263567540

[1, 0, 2, 6, 60, 560, 7350, 111552, 2009672, 41378976, 963527850, 25009038560, 716437784172, 22453784964624, 764345507271710, 28085186967504240, 1107971902218683280, 46710909213378892352, 2095883952368863510098, 99724281567446320231104, 5015524096516005263567540]

cp's OEIS Frontend

A215720 The number of functions f:{1,2,...,n}->{1,2,...,n}, endofunctions, such that exactly one nonrecurrent element is mapped into each recurrent element.

Table of values

List of values