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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.

A230647 Number of nX3 0..2 white square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j).

Table of values

n a(n)
1 0
2 3
3 3
4 21
5 27
6 177
7 231
8 1509
9 1971
10 12873
11 16815
12 109821
13 143451
14 936897
15 1223799
16 7992789
17 10440387
18 68187513
19 89068287
20 581716461
21 759853035
22 4962698097
23 6482404167
24 42337417029
25 55302225363
26 361185960873
27 471790411599

List of values

[0, 3, 3, 21, 27, 177, 231, 1509, 1971, 12873, 16815, 109821, 143451, 936897, 1223799, 7992789, 10440387, 68187513, 89068287, 581716461, 759853035, 4962698097, 6482404167, 42337417029, 55302225363, 361185960873, 471790411599]

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

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