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.

A209981 Number of singular 2 X 2 matrices having all elements in {-n,...,n}.

Table of values

n a(n)
0 1
1 33
2 129
3 289
4 545
5 833
6 1313
7 1729
8 2369
9 3041
10 3905
11 4577
12 5857
13 6657
14 7905
15 9345
16 10881
17 11937
18 13953
19 15137
20 17441
21 19521
22 21537
23 22977
24 26177
25 28257
26 30657
27 33249
28 36577
29 38401
30 42721
31 44673
32 48257
33 51617
34 54785
35 58529
36 63905

List of values

[1, 33, 129, 289, 545, 833, 1313, 1729, 2369, 3041, 3905, 4577, 5857, 6657, 7905, 9345, 10881, 11937, 13953, 15137, 17441, 19521, 21537, 22977, 26177, 28257, 30657, 33249, 36577, 38401, 42721, 44673, 48257, 51617, 54785, 58529, 63905]