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.

A206688 Number of nX4 0..3 arrays with no element equal to another within two positions in the same row or column, and new values 0..3 introduced in row major order.

Table of values

n a(n)
1 2
2 36
3 176
4 916
5 4704
6 24492
7 127008
8 660888
9 3436488
10 17884080
11 93059016
12 484334480
13 2520695968
14 13119605656
15 68284077520
16 355405952496
17 1849822022856
18 9628019156288
19 50112266984832
20 260826450827576
21 1357560738338768

List of values

[2, 36, 176, 916, 4704, 24492, 127008, 660888, 3436488, 17884080, 93059016, 484334480, 2520695968, 13119605656, 68284077520, 355405952496, 1849822022856, 9628019156288, 50112266984832, 260826450827576, 1357560738338768]

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

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