cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A047171 Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-1)/2.

Table of values

n a(n)
0 0
1 0
2 0
3 2
4 3
5 9
6 14
7 34
8 55
9 125
10 209
11 461
12 791
13 1715
14 3002
15 6434
16 11439
17 24309
18 43757
19 92377
20 167959
21 352715
22 646645
23 1352077
24 2496143
25 5200299
26 9657699
27 20058299
28 37442159
29 77558759
30 145422674
31 300540194
32 565722719
33 1166803109
34 2203961429
35 4537567649

List of values

[0, 0, 0, 2, 3, 9, 14, 34, 55, 125, 209, 461, 791, 1715, 3002, 6434, 11439, 24309, 43757, 92377, 167959, 352715, 646645, 1352077, 2496143, 5200299, 9657699, 20058299, 37442159, 77558759, 145422674, 300540194, 565722719, 1166803109, 2203961429, 4537567649]