cp's OEIS Frontend

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.

A239601 Number of 3Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.

Table of values

n a(n)
1 4
2 4
3 31
4 187
5 1310
6 9806
7 76769
8 611126
9 4929897
10 39990616
11 325367130
12 2651480323
13 21625911002
14 176464323565
15 1440276473432
16 11756877845964
17 95977420564389
18 783542978550992
19 6396841387070227
20 52224370266137630
21 426366892135459667

List of values

[4, 4, 31, 187, 1310, 9806, 76769, 611126, 4929897, 39990616, 325367130, 2651480323, 21625911002, 176464323565, 1440276473432, 11756877845964, 95977420564389, 783542978550992, 6396841387070227, 52224370266137630, 426366892135459667]

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

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