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.

A177285 Number of permutations of 2 copies of 1..n with all adjacent differences <= 4 in absolute value.

Table of values

n a(n)
0 1
1 1
2 6
3 90
4 2520
5 113400
6 3356640
7 75336660
8 1500131820
9 29660400822
10 620330067782
11 13125403608162
12 274194614811528
13 5605288189594200
14 112437639146871360
15 2235073249396108440
16 44209749453949113840
17 870798759948756386976
18 17069437222534487122608
19 332789644153015982087550
20 6455422726721469064982952

List of values

[1, 1, 6, 90, 2520, 113400, 3356640, 75336660, 1500131820, 29660400822, 620330067782, 13125403608162, 274194614811528, 5605288189594200, 112437639146871360, 2235073249396108440, 44209749453949113840, 870798759948756386976, 17069437222534487122608, 332789644153015982087550, 6455422726721469064982952]

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

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