A047182 - cp's OEIS frontend

A047182 Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-2)/2.

n	a(n)
1	0
2	0
3	0
4	3
5	4
6	14
7	20
8	55
9	83
10	209
11	329
12	791
13	1286
14	3002
15	5004
16	11439
17	19447
18	43757
19	75581
20	167959
21	293929
22	646645
23	1144065
24	2496143
25	4457399
26	9657699
27	17383859
28	37442159
29	67863914
30	145422674
31	265182524
32	565722719
33	1037158319

[0, 0, 0, 3, 4, 14, 20, 55, 83, 209, 329, 791, 1286, 3002, 5004, 11439, 19447, 43757, 75581, 167959, 293929, 646645, 1144065, 2496143, 4457399, 9657699, 17383859, 37442159, 67863914, 145422674, 265182524, 565722719, 1037158319]

cp's OEIS Frontend

A047182 Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-2)/2.

Table of values

List of values