A116218 - cp's OEIS frontend

A116218 If X_1,...,X_n is a partition of a 2n-set X into 2-blocks (or pairs) then a(n) is equal to the number of permutations f of X such that f(X_i) != X_i for all i=1,...n.

n	a(n)
0	1
1	0
2	20
3	592
4	35088
5	3252608
6	437765440
7	80766186240
8	19580003614976
9	6038002429456384
10	2308538525796209664
11	1071858241055770480640
12	594103565746026102722560
13	387504996819754568329494528
14	293818792387460667662661926912
15	256273357771747968541309427187712

[1, 0, 20, 592, 35088, 3252608, 437765440, 80766186240, 19580003614976, 6038002429456384, 2308538525796209664, 1071858241055770480640, 594103565746026102722560, 387504996819754568329494528, 293818792387460667662661926912, 256273357771747968541309427187712]

cp's OEIS Frontend

A116218 If X_1,...,X_n is a partition of a 2n-set X into 2-blocks (or pairs) then a(n) is equal to the number of permutations f of X such that f(X_i) != X_i for all i=1,...n.

Table of values

List of values