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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.

A259217 Number of (n+1) X (3+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0011 or 0101.

Table of values

n a(n)
1 24
2 40
3 66
4 112
5 192
6 334
7 588
8 1048
9 1890
10 3448
11 6360
12 11854
13 22308
14 42352
15 81042
16 156160
17 302736
18 589966
19 1154844
20 2269096
21 4472514
22 8838760
23 17505576
24 34732942
25 69015732
26 137303104
27 273427698
28 544948528
29 1086811680
30 2168631118
31 4329184620

List of values

[24, 40, 66, 112, 192, 334, 588, 1048, 1890, 3448, 6360, 11854, 22308, 42352, 81042, 156160, 302736, 589966, 1154844, 2269096, 4472514, 8838760, 17505576, 34732942, 69015732, 137303104, 273427698, 544948528, 1086811680, 2168631118, 4329184620]

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

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