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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.

A239399 Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of elements above it, modulo 4.

Table of values

n a(n)
1 4
2 23
3 129
4 698
5 3805
6 20818
7 113774
8 621754
9 3399032
10 18582965
11 101593258
12 555419633
13 3036563927
14 16601366841
15 90762262155
16 496211843813
17 2712870511114
18 14831702705726
19 81087325012785
20 443317575022163
21 2423689199017701
22 13250702601112477
23 72443743963082659
24 396061718589309511

List of values

[4, 23, 129, 698, 3805, 20818, 113774, 621754, 3399032, 18582965, 101593258, 555419633, 3036563927, 16601366841, 90762262155, 496211843813, 2712870511114, 14831702705726, 81087325012785, 443317575022163, 2423689199017701, 13250702601112477, 72443743963082659, 396061718589309511]

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

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