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.

A220330 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..1 3Xn array.

Table of values

n a(n)
1 1
2 12
3 92
4 572
5 4062
6 29467
7 213225
8 1540686
9 11163495
10 80656708
11 581473349
12 4190483128
13 30199355040
14 217538559602
15 1566825952174
16 11283025994195
17 81236036737903
18 584831754731217
19 4210022381269251
20 30304818855812080

List of values

[1, 12, 92, 572, 4062, 29467, 213225, 1540686, 11163495, 80656708, 581473349, 4190483128, 30199355040, 217538559602, 1566825952174, 11283025994195, 81236036737903, 584831754731217, 4210022381269251, 30304818855812080]

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

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