A273652 - cp's OEIS frontend

A273652 Number of forests of labeled rooted trees of height at most 1, with n labels, two of which are used for root nodes and any root may contain >= 1 labels.

n	a(n)
2	2
3	9
4	30
5	90
6	255
7	693
8	1820
9	4644
10	11565
11	28215
12	67650
13	159822
14	372827
15	860265
16	1966200
17	4456584
18	10027161
19	22413483
20	49807550
21	110100690
22	242221287
23	530579709
24	1157628180
25	2516582700
26	5452595525
27	11777605983
28	25367150970
29	54492397974
30	116769423795

[2, 9, 30, 90, 255, 693, 1820, 4644, 11565, 28215, 67650, 159822, 372827, 860265, 1966200, 4456584, 10027161, 22413483, 49807550, 110100690, 242221287, 530579709, 1157628180, 2516582700, 5452595525, 11777605983, 25367150970, 54492397974, 116769423795]

cp's OEIS Frontend

A273652 Number of forests of labeled rooted trees of height at most 1, with n labels, two of which are used for root nodes and any root may contain >= 1 labels.

Table of values

List of values