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.

A301843 Number of 3Xn 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.

Table of values

n a(n)
1 4
2 32
3 139
4 678
5 3182
6 15199
7 72514
8 346244
9 1653214
10 7893443
11 37688062
12 179946317
13 859175558
14 4102237937
15 19586633161
16 93518758201
17 446516665710
18 2131948036306
19 10179244758257
20 48602040050313
21 232056341426270
22 1107981178164225

List of values

[4, 32, 139, 678, 3182, 15199, 72514, 346244, 1653214, 7893443, 37688062, 179946317, 859175558, 4102237937, 19586633161, 93518758201, 446516665710, 2131948036306, 10179244758257, 48602040050313, 232056341426270, 1107981178164225]

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

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