A254570 - cp's OEIS frontend

A254570 The number of unordered pairs (f,g) of functions from {1..n} to itself such that fg=gf (i.e., f(g(i))=g(f(i)) for all i) where f and g are distinct.

n	a(n)
1	0
2	3
3	57
4	1284
5	34220
6	1098720
7	41579328
8	1832244288
9	92830006368
10	5353120671120
11	348383876993900
12	25409389391925264
13	2064511110000765192
14	185885772163424273304
15	18458953746901624026000
16	2012589235930543617012480
17	239897773975844015012351360
18	31132547318002718989156350240
19	4380969784826872849927354999092
20	665896601825393760478978112600400

[0, 3, 57, 1284, 34220, 1098720, 41579328, 1832244288, 92830006368, 5353120671120, 348383876993900, 25409389391925264, 2064511110000765192, 185885772163424273304, 18458953746901624026000, 2012589235930543617012480, 239897773975844015012351360, 31132547318002718989156350240, 4380969784826872849927354999092, 665896601825393760478978112600400]

cp's OEIS Frontend

A254570 The number of unordered pairs (f,g) of functions from {1..n} to itself such that fg=gf (i.e., f(g(i))=g(f(i)) for all i) where f and g are distinct.

Table of values

List of values