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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.

A240401 Number of nX2 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.

Table of values

n a(n)
1 2
2 5
3 14
4 24
5 77
6 182
7 397
8 1164
9 2626
10 6439
11 17045
12 39465
13 100175
14 251538
15 602316
16 1525842
17 3756635
18 9193532
19 23052218
20 56571408
21 139814332
22 347712483
23 855278021
24 2119654735
25 5248572774
26 12946151193
27 32079791328
28 79306295913
29 195965663917

List of values

[2, 5, 14, 24, 77, 182, 397, 1164, 2626, 6439, 17045, 39465, 100175, 251538, 602316, 1525842, 3756635, 9193532, 23052218, 56571408, 139814332, 347712483, 855278021, 2119654735, 5248572774, 12946151193, 32079791328, 79306295913, 195965663917]

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

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