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.

A199699 Number of -3..3 arrays x(0..n-1) of n elements with zero sum and no two neighbors equal.

Table of values

n a(n)
1 1
2 6
3 32
4 168
5 892
6 4964
7 27854
8 156920
9 891684
10 5095360
11 29236016
12 168361392
13 972601784
14 5633548460
15 32706291872
16 190266981972
17 1108856802378
18 6472638961608
19 37836350087956
20 221461180199752
21 1297757839607606

List of values

[1, 6, 32, 168, 892, 4964, 27854, 156920, 891684, 5095360, 29236016, 168361392, 972601784, 5633548460, 32706291872, 190266981972, 1108856802378, 6472638961608, 37836350087956, 221461180199752, 1297757839607606]