A048080 - cp's OEIS frontend

A048080 Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= (n+2)/3.

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	3
9	18
10	24
11	84
12	224
13	280
14	630
15	1270
16	1527
17	2937
18	5742
19	6930
20	15015
21	35035
22	44044
23	108164
24	260064
25	328944
26	767244
27	1720944
28	2152710
29	4738410
30	10329750
31	12890614
32	28583709
33	64071194
34	80628669
35	184657869

[0, 0, 0, 0, 0, 0, 0, 3, 18, 24, 84, 224, 280, 630, 1270, 1527, 2937, 5742, 6930, 15015, 35035, 44044, 108164, 260064, 328944, 767244, 1720944, 2152710, 4738410, 10329750, 12890614, 28583709, 64071194, 80628669, 184657869]

cp's OEIS Frontend

A048080 Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= (n+2)/3.

Table of values

List of values