A368599 - cp's OEIS frontend

A368599 Number of non-isomorphic n-element sets of singletons or pairs of elements of {1..n} with union {1..n}, or unlabeled loop-graphs with n edges covering n vertices.

n	a(n)
0	1
1	1
2	2
3	5
4	13
5	34
6	97
7	277
8	825
9	2486
10	7643
11	23772
12	74989
13	238933
14	769488
15	2500758
16	8199828
17	27106647
18	90316944
19	303182461
20	1025139840
21	3490606305
22	11967066094
23	41302863014
24	143493606215
25	501772078429
26	1765928732426
27	6254738346969
28	22294413256484
29	79968425399831

[1, 1, 2, 5, 13, 34, 97, 277, 825, 2486, 7643, 23772, 74989, 238933, 769488, 2500758, 8199828, 27106647, 90316944, 303182461, 1025139840, 3490606305, 11967066094, 41302863014, 143493606215, 501772078429, 1765928732426, 6254738346969, 22294413256484, 79968425399831]

cp's OEIS Frontend

A368599 Number of non-isomorphic n-element sets of singletons or pairs of elements of {1..n} with union {1..n}, or unlabeled loop-graphs with n edges covering n vertices.

Table of values

List of values