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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.

A232377 Number of 2Xn 0..3 arrays with every 0 next to a 1, every 1 next to a 2 and every 2 next to a 3 horizontally, diagonally or antidiagonally, and no adjacent values equal.

Table of values

n a(n)
1 1
2 14
3 74
4 296
5 1130
6 4682
7 19448
8 79592
9 326810
10 1343042
11 5516132
12 22658744
13 93073958
14 382310690
15 1570402928
16 6450645104
17 26496901994
18 108839752922
19 447074397188
20 1836420218672
21 7543351642070
22 30985365821066
23 127276699845344
24 522806747988728
25 2147501432084138

List of values

[1, 14, 74, 296, 1130, 4682, 19448, 79592, 326810, 1343042, 5516132, 22658744, 93073958, 382310690, 1570402928, 6450645104, 26496901994, 108839752922, 447074397188, 1836420218672, 7543351642070, 30985365821066, 127276699845344, 522806747988728, 2147501432084138]

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

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