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.

A001267 One-half the number of permutations of length n with exactly 3 rising or falling successions.

Table of values

n a(n)
0 0
1 0
2 0
3 0
4 1
5 8
6 60
7 444
8 3599
9 32484
10 325322
11 3582600
12 43029621
13 559774736
14 7841128936
15 117668021988
16 1883347579515
17 32026067455084
18 576605574327174
19 10957672400252944
20 219190037987444577
21 4603645435776504120
22 101292568208941883236
23 2329975164242735146316

List of values

[0, 0, 0, 0, 1, 8, 60, 444, 3599, 32484, 325322, 3582600, 43029621, 559774736, 7841128936, 117668021988, 1883347579515, 32026067455084, 576605574327174, 10957672400252944, 219190037987444577, 4603645435776504120, 101292568208941883236, 2329975164242735146316]

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

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