A368596 - cp's OEIS frontend

A368596 Number of n-element sets of singletons or pairs of distinct elements of {1..n}, or loop graphs with n edges, such that it is not possible to choose a different element from each.

n	a(n)
0	0
1	0
2	0
3	3
4	66
5	1380
6	31460
7	800625
8	22758918
9	718821852
10	25057509036
11	957657379437
12	39878893266795
13	1799220308202603
14	87502582432459584
15	4566246347310609247
16	254625879822078742956
17	15115640124974801925030
18	952050565540607423524658
19	63425827673509972464868323

[0, 0, 0, 3, 66, 1380, 31460, 800625, 22758918, 718821852, 25057509036, 957657379437, 39878893266795, 1799220308202603, 87502582432459584, 4566246347310609247, 254625879822078742956, 15115640124974801925030, 952050565540607423524658, 63425827673509972464868323]

cp's OEIS Frontend

A368596 Number of n-element sets of singletons or pairs of distinct elements of {1..n}, or loop graphs with n edges, such that it is not possible to choose a different element from each.

Table of values

List of values