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.

A266573 Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its northwest or southwest neighbor modulo 3 and the upper left element equal to 0.

Table of values

n a(n)
1 2
2 5
3 15
4 109
5 574
6 2840
7 13767
8 71646
9 390862
10 2170370
11 11989812
12 66094738
13 366119221
14 2044786962
15 11503587136
16 65003352026
17 368281990242
18 2091514533360
19 11909843102866
20 68009104297282
21 389348569168108
22 2233795881384252

List of values

[2, 5, 15, 109, 574, 2840, 13767, 71646, 390862, 2170370, 11989812, 66094738, 366119221, 2044786962, 11503587136, 65003352026, 368281990242, 2091514533360, 11909843102866, 68009104297282, 389348569168108, 2233795881384252]

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

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