A005199 - cp's OEIS frontend

A005199 a(n) = Sum_t t*F(n,t), where F(n,t) is the number of forests with n (unlabeled) nodes and exactly t trees, all of which are planted (that is, rooted trees in which the root has degree 1).

n	a(n)
1	0
2	1
3	1
4	4
5	6
6	18
7	35
8	93
9	214
10	549
11	1362
12	3534
13	9102
14	23951
15	63192
16	168561
17	451764
18	1219290
19	3305783
20	9008027
21	24643538
22	67681372
23	186504925
24	515566016
25	1429246490
26	3972598378
27	11068477743
28	30908170493
29	86488245455
30	242481159915
31	681048784377
32	1916051725977
33	5399062619966

[0, 1, 1, 4, 6, 18, 35, 93, 214, 549, 1362, 3534, 9102, 23951, 63192, 168561, 451764, 1219290, 3305783, 9008027, 24643538, 67681372, 186504925, 515566016, 1429246490, 3972598378, 11068477743, 30908170493, 86488245455, 242481159915, 681048784377, 1916051725977, 5399062619966]

cp's OEIS Frontend

A005199 a(n) = Sum_t t*F(n,t), where F(n,t) is the number of forests with n (unlabeled) nodes and exactly t trees, all of which are planted (that is, rooted trees in which the root has degree 1).

Table of values

List of values