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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.

A264515 Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change -1,0 0,2 -1,-2 or 1,0.

Table of values

n a(n)
1 1
2 1
3 9
4 36
5 144
6 576
7 2116
8 8281
9 31329
10 121801
11 467856
12 1809025
13 6969600
14 26884225
15 103632400
16 399560121
17 1540484001
18 5939322489
19 22899558276
20 88289802496
21 340406901136
22 1312449766884
23 5060209759081
24 19509827162049
25 75220946346001

List of values

[1, 1, 9, 36, 144, 576, 2116, 8281, 31329, 121801, 467856, 1809025, 6969600, 26884225, 103632400, 399560121, 1540484001, 5939322489, 22899558276, 88289802496, 340406901136, 1312449766884, 5060209759081, 19509827162049, 75220946346001]

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

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