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.

A002173 a(n) = Sum_{d|n, d == 1 mod 4} d^2 - Sum_{d|n, d == 3 mod 4} d^2.

Table of values

n a(n)
1 1
2 1
3 -8
4 1
5 26
6 -8
7 -48
8 1
9 73
10 26
11 -120
12 -8
13 170
14 -48
15 -208
16 1
17 290
18 73
19 -360
20 26
21 384
22 -120
23 -528
24 -8
25 651
26 170
27 -656
28 -48
29 842
30 -208
31 -960
32 1
33 960
34 290
35 -1248
36 73
37 1370
38 -360
39 -1360
40 26
41 1682
42 384
43 -1848
44 -120
45 1898
46 -528
47 -2208
48 -8
49 2353
50 651
51 -2320
52 170

List of values

[1, 1, -8, 1, 26, -8, -48, 1, 73, 26, -120, -8, 170, -48, -208, 1, 290, 73, -360, 26, 384, -120, -528, -8, 651, 170, -656, -48, 842, -208, -960, 1, 960, 290, -1248, 73, 1370, -360, -1360, 26, 1682, 384, -1848, -120, 1898, -528, -2208, -8, 2353, 651, -2320, 170]