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.

A268768 Number of n X 2 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

Table of values

n a(n)
1 3
2 12
3 32
4 100
5 248
6 620
7 1456
8 3380
9 7656
10 17148
11 37920
12 83140
13 180824
14 390796
15 839824
16 1796180
17 3825352
18 8116764
19 17165568
20 36195300
21 76118840
22 159694252
23 334301552
24 698429300
25 1456510888
26 3032326460
27 6303262176
28 13083742980

List of values

[3, 12, 32, 100, 248, 620, 1456, 3380, 7656, 17148, 37920, 83140, 180824, 390796, 839824, 1796180, 3825352, 8116764, 17165568, 36195300, 76118840, 159694252, 334301552, 698429300, 1456510888, 3032326460, 6303262176, 13083742980]

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

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