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.

A188242 Number of arrangements of n+2 nonzero numbers x(i) in -2..2 with the sum of x(i)*x(i+1) equal to zero.

Table of values

n a(n)
1 16
2 20
3 120
4 300
5 1284
6 4132
7 16272
8 57808
9 223308
10 828456
11 3193588
12 12106616
13 46777036
14 179484068
15 695670728
16 2689241588
17 10454975104
18 40616587968
19 158328346172
20 617266507080
21 2411727117520
22 9427476168776
23 36906793159556

List of values

[16, 20, 120, 300, 1284, 4132, 16272, 57808, 223308, 828456, 3193588, 12106616, 46777036, 179484068, 695670728, 2689241588, 10454975104, 40616587968, 158328346172, 617266507080, 2411727117520, 9427476168776, 36906793159556]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.