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.

A317139 Number of permutations of [n] with exactly floor(n/2) increasing runs of length two.

Table of values

n a(n)
0 1
1 1
2 1
3 4
4 5
5 43
6 61
7 906
8 1385
9 31493
10 50521
11 1629248
12 2702765
13 117248463
14 199360981
15 11190963430
16 19391512145
17 1367267690953
18 2404879675441
19 208031951035452
20 370371188237525
21 38563334673062963
22 69348874393137901
23 8554779137299629314
24 15514534163557086905

List of values

[1, 1, 1, 4, 5, 43, 61, 906, 1385, 31493, 50521, 1629248, 2702765, 117248463, 199360981, 11190963430, 19391512145, 1367267690953, 2404879675441, 208031951035452, 370371188237525, 38563334673062963, 69348874393137901, 8554779137299629314, 15514534163557086905]

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

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