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.

A201081 Number of -1..1 arrays of n elements with first and second differences also in -1..1.

Table of values

n a(n)
1 3
2 7
3 13
4 25
5 47
6 89
7 169
8 321
9 609
10 1155
11 2191
12 4157
13 7887
14 14963
15 28387
16 53855
17 102173
18 193841
19 367751
20 697689
21 1323641
22 2511185
23 4764169
24 9038483
25 17147623
26 32532117
27 61719263
28 117092515
29 222145507
30 421449879
31 799566029
32 1516920201

List of values

[3, 7, 13, 25, 47, 89, 169, 321, 609, 1155, 2191, 4157, 7887, 14963, 28387, 53855, 102173, 193841, 367751, 697689, 1323641, 2511185, 4764169, 9038483, 17147623, 32532117, 61719263, 117092515, 222145507, 421449879, 799566029, 1516920201]