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.

A084894 Number of permutations of length n such that at least one absolute difference between consecutive elements has a distinct partner.

Table of values

n a(n)
1 0
2 0
3 2
4 20
5 112
6 696
7 5008
8 40280
9 362760
10 3628504
11 39916152
12 479000272
13 6227017600
14 87178281288
15 1307674342408
16 20922789832080
17 355687427952808
18 6402373705217304
19 121645100407380704
20 2432902008173142656
21 51090942171698988176
22 1124000727777569109296

List of values

[0, 0, 2, 20, 112, 696, 5008, 40280, 362760, 3628504, 39916152, 479000272, 6227017600, 87178281288, 1307674342408, 20922789832080, 355687427952808, 6402373705217304, 121645100407380704, 2432902008173142656, 51090942171698988176, 1124000727777569109296]

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

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