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.

A221291 Equals two maps: number of 3Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 3Xn array.

Table of values

n a(n)
1 1
2 12
3 92
4 673
5 5912
6 48298
7 396846
8 3240527
9 26241353
10 211785583
11 1703772887
12 13679840407
13 109689414233
14 878752161168
15 7035829547262
16 56311795445487

List of values

[1, 12, 92, 673, 5912, 48298, 396846, 3240527, 26241353, 211785583, 1703772887, 13679840407, 109689414233, 878752161168, 7035829547262, 56311795445487]

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

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