A185025 - cp's OEIS frontend

A185025 Triangular array read by rows: T(n,k) is the number of functions f:{1,2,...,n} -> {1,2,...,n} that have exactly k 2-cycles for n >= 0 and 0 <= k <= floor(n/2).

n	a(n)
0	1
1	1
2	3
3	1
4	18
5	9
6	163
7	90
8	3
9	1950
10	1100
11	75
12	28821
13	16245
14	1575
15	15
16	505876
17	283122
18	33810
19	735
20	10270569
21	5699932
22	780150
23	26460
24	105
25	236644092
26	130267440
27	19615932
28	884520
29	8505
30	6098971555
31	3332614725
32	538325550
33	29619450
34	467775
35	945

[1, 1, 3, 1, 18, 9, 163, 90, 3, 1950, 1100, 75, 28821, 16245, 1575, 15, 505876, 283122, 33810, 735, 10270569, 5699932, 780150, 26460, 105, 236644092, 130267440, 19615932, 884520, 8505, 6098971555, 3332614725, 538325550, 29619450, 467775, 945]

cp's OEIS Frontend

A185025 Triangular array read by rows: T(n,k) is the number of functions f:{1,2,...,n} -> {1,2,...,n} that have exactly k 2-cycles for n >= 0 and 0 <= k <= floor(n/2).

Table of values

List of values