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.

A228422 Number of permutations of [n] with exactly two (possibly overlapping) occurrences of some of the consecutive patterns 123, 1432, 2431, 3421.

Table of values

n a(n)
0 0
1 0
2 0
3 0
4 1
5 14
6 164
7 1589
8 15034
9 139465
10 1334945
11 13108425
12 134906641
13 1443572465
14 16238742806
15 190546010823
16 2347715040542
17 30162115442344
18 405859441345002
19 5684963539755583
20 83163913991455832
21 1263763900212930657
22 20000260465018111763

List of values

[0, 0, 0, 0, 1, 14, 164, 1589, 15034, 139465, 1334945, 13108425, 134906641, 1443572465, 16238742806, 190546010823, 2347715040542, 30162115442344, 405859441345002, 5684963539755583, 83163913991455832, 1263763900212930657, 20000260465018111763]

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

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