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.

A122670 If n mod 4 = 2 or n mod 4 = 3 then a(n) = 0 else let m=floor(n/4), then a(n) = (2*m)!/m!.

Table of values

n a(n)
0 1
1 1
2 0
3 0
4 2
5 2
6 0
7 0
8 12
9 12
10 0
11 0
12 120
13 120
14 0
15 0
16 1680
17 1680
18 0
19 0
20 30240
21 30240
22 0
23 0
24 665280
25 665280
26 0
27 0
28 17297280
29 17297280
30 0
31 0
32 518918400
33 518918400
34 0
35 0
36 17643225600
37 17643225600
38 0
39 0
40 670442572800
41 670442572800
42 0
43 0
44 28158588057600
45 28158588057600
46 0
47 0
48 1295295050649600

List of values

[1, 1, 0, 0, 2, 2, 0, 0, 12, 12, 0, 0, 120, 120, 0, 0, 1680, 1680, 0, 0, 30240, 30240, 0, 0, 665280, 665280, 0, 0, 17297280, 17297280, 0, 0, 518918400, 518918400, 0, 0, 17643225600, 17643225600, 0, 0, 670442572800, 670442572800, 0, 0, 28158588057600, 28158588057600, 0, 0, 1295295050649600]