A047168 - cp's OEIS frontend

A047168 Number of nonempty subsets of {1,2,...,n} in which exactly 4/5 of the elements are <= n/2.

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	4
9	5
10	25
11	30
12	90
13	105
14	245
15	280
16	588
17	666
18	1458
19	1665
20	4125
21	4785
22	12705
23	14850
24	38830
25	45331
26	113399
27	131859
28	320411
29	371735
30	903175
31	1048840
32	2594540
33	3021240
34	7594920
35	8863698
36	22366458
37	26122302
38	65579982
39	76575225
40	191126529

[0, 0, 0, 0, 0, 0, 0, 4, 5, 25, 30, 90, 105, 245, 280, 588, 666, 1458, 1665, 4125, 4785, 12705, 14850, 38830, 45331, 113399, 131859, 320411, 371735, 903175, 1048840, 2594540, 3021240, 7594920, 8863698, 22366458, 26122302, 65579982, 76575225, 191126529]

cp's OEIS Frontend

A047168 Number of nonempty subsets of {1,2,...,n} in which exactly 4/5 of the elements are <= n/2.

Table of values

List of values