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.

A105861 a(n) = (n/2) * Sum_{k=0..n} binomial(n,k)/gcd(n,k).

Table of values

n a(n)
1 1
2 3
3 10
4 23
5 76
6 102
7 442
8 695
9 1792
10 2828
11 11254
12 13334
13 53236
14 65418
15 155110
16 347319
17 1114096
18 1259328
19 4980718
20 6223148
21 15033700
22 27548678
23 96468970
24 108761942
25 352992576
26 529504212
27 1381165192
28 2314603370
29 7784628196

List of values

[1, 3, 10, 23, 76, 102, 442, 695, 1792, 2828, 11254, 13334, 53236, 65418, 155110, 347319, 1114096, 1259328, 4980718, 6223148, 15033700, 27548678, 96468970, 108761942, 352992576, 529504212, 1381165192, 2314603370, 7784628196]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.