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.

A117574 Total number of permutations p of [n] such that |p(i+3) - p(i)| is not equal to 3 for 1 <= i <= n-3.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 20
5 80
6 384
7 2240
8 15424
9 123456
10 1110928
11 11287232
12 127016304
13 1565107248
14 20935873872
15 301974271248
16 4669727780624
17 77046043259824
18 1350585114106416
19 25062108668100208
20 490725684463001488
21 10109820295907492304

List of values

[1, 1, 2, 6, 20, 80, 384, 2240, 15424, 123456, 1110928, 11287232, 127016304, 1565107248, 20935873872, 301974271248, 4669727780624, 77046043259824, 1350585114106416, 25062108668100208, 490725684463001488, 10109820295907492304]

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

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