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.

A307090 Number triangle T(n,k) = Sum_{j=0..n-k} (-1)^j * binomial(k,2*j) * binomial(n-k,2*j).

Table of values

n a(n)
0 1
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 1
12 0
13 1
14 1
15 1
16 1
17 -2
18 -2
19 1
20 1
21 1
22 1
23 -5
24 -8
25 -5
26 1
27 1
28 1
29 1
30 -9
31 -17
32 -17
33 -9
34 1
35 1
36 1
37 1
38 -14
39 -29
40 -34
41 -29
42 -14
43 1
44 1
45 1
46 1
47 -20
48 -44
49 -54
50 -54
51 -44
52 -20
53 1
54 1
55 1
56 1
57 -27
58 -62
59 -74
60 -74
61 -74
62 -62
63 -27
64 1
65 1
66 1
67 1
68 -35
69 -83
70 -90
71 -74
72 -74
73 -90
74 -83
75 -35
76 1
77 1

List of values

[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, -2, -2, 1, 1, 1, 1, -5, -8, -5, 1, 1, 1, 1, -9, -17, -17, -9, 1, 1, 1, 1, -14, -29, -34, -29, -14, 1, 1, 1, 1, -20, -44, -54, -54, -44, -20, 1, 1, 1, 1, -27, -62, -74, -74, -74, -62, -27, 1, 1, 1, 1, -35, -83, -90, -74, -74, -90, -83, -35, 1, 1]