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.

A222373 Number of nX2 0..3 arrays with no more than floor(nX2/2) elements unequal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..3 order.

Table of values

n a(n)
1 1
2 1
3 5
4 18
5 63
6 234
7 1163
8 4953
9 24021
10 109395
11 536457
12 2526558
13 12324313
14 59135699
15 288057673
16 1396084937
17 6800380165
18 33152287976
19 161670473265
20 790996243845
21 3863624579433
22 18948369852560
23 92716137764021
24 455475835479225

List of values

[1, 1, 5, 18, 63, 234, 1163, 4953, 24021, 109395, 536457, 2526558, 12324313, 59135699, 288057673, 1396084937, 6800380165, 33152287976, 161670473265, 790996243845, 3863624579433, 18948369852560, 92716137764021, 455475835479225]

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

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