A281881 - cp's OEIS frontend

A281881 Triangle read by rows: T(n,k) (n>=1, 2<=k<=n+1) is the number of k-sequences of balls colored with at most n colors such that exactly one ball is of a color seen previously in the sequence.

n	a(n)
1	1
2	2
3	6
4	3
5	18
6	36
7	4
8	36
9	144
10	240
11	5
12	60
13	360
14	1200
15	1800
16	6
17	90
18	720
19	3600
20	10800
21	15120
22	7
23	126
24	1260
25	8400
26	37800
27	105840
28	141120
29	8
30	168
31	2016
32	16800
33	100800
34	423360
35	1128960
36	1451520

[1, 2, 6, 3, 18, 36, 4, 36, 144, 240, 5, 60, 360, 1200, 1800, 6, 90, 720, 3600, 10800, 15120, 7, 126, 1260, 8400, 37800, 105840, 141120, 8, 168, 2016, 16800, 100800, 423360, 1128960, 1451520]

cp's OEIS Frontend

A281881 Triangle read by rows: T(n,k) (n>=1, 2<=k<=n+1) is the number of k-sequences of balls colored with at most n colors such that exactly one ball is of a color seen previously in the sequence.

Table of values

List of values