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.

A107847 Related to sums of the n-th roots of unity: sums in a circular wedge (excluding the origin).

Table of values

n a(n)
1 1
2 1
3 2
4 3
5 6
6 9
7 18
8 30
9 56
10 99
11 186
12 333
13 630
14 1161
15 2182
16 4080
17 7710
18 14508
19 27594
20 52371
21 99858
22 190557
23 364722
24 698634
25 1342176
26 2580795
27 4971008
28 9586377
29 18512790
30 35786499
31 69273666
32 134215680
33 260300986
34 505286415
35 981706806

List of values

[1, 1, 2, 3, 6, 9, 18, 30, 56, 99, 186, 333, 630, 1161, 2182, 4080, 7710, 14508, 27594, 52371, 99858, 190557, 364722, 698634, 1342176, 2580795, 4971008, 9586377, 18512790, 35786499, 69273666, 134215680, 260300986, 505286415, 981706806]