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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.

A229444 Number of n X 7 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.

Table of values

n a(n)
1 9
2 32
3 138
4 665
5 3184
6 14536
7 62205
8 247607
9 914271
10 3133068
11 9990129
12 29755249
13 83162347
14 219151523
15 547116607
16 1299869098
17 2951439969
18 6429248828
19 13483439736
20 27310437901
21 53577074678
22 102061137870
23 189220453845

List of values

[9, 32, 138, 665, 3184, 14536, 62205, 247607, 914271, 3133068, 9990129, 29755249, 83162347, 219151523, 547116607, 1299869098, 2951439969, 6429248828, 13483439736, 27310437901, 53577074678, 102061137870, 189220453845]

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

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