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.

A159718 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 local maxima.

Table of values

n a(n)
1 0
2 0
3 0
4 88
5 33600
6 3821760
7 272509552
8 15313310208
9 750469872312
10 33813251867920
11 1443455210369040
12 59454199364673024
13 2389923754993613176
14 94450458835284703536
15 3687585353084799432720
16 142691482885508987276800
17 5484263653598164634676600
18 209677462059979688650122960

List of values

[0, 0, 0, 88, 33600, 3821760, 272509552, 15313310208, 750469872312, 33813251867920, 1443455210369040, 59454199364673024, 2389923754993613176, 94450458835284703536, 3687585353084799432720, 142691482885508987276800, 5484263653598164634676600, 209677462059979688650122960]

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

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