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.

A221508 Number of 2Xn arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.

Table of values

n a(n)
1 0
2 9
3 44
4 446
5 3334
6 27540
7 219070
8 1766136
9 14168766
10 113870162
11 914550470
12 7346946970
13 59015933032
14 474072774244
15 3808166264624
16 30590638905810
17 245731343642532
18 1973934759524284
19 15856413036814582
20 127372929035331130

List of values

[0, 9, 44, 446, 3334, 27540, 219070, 1766136, 14168766, 113870162, 914550470, 7346946970, 59015933032, 474072774244, 3808166264624, 30590638905810, 245731343642532, 1973934759524284, 15856413036814582, 127372929035331130]

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

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