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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.

A262128 Number of permutations p of [n] such that the up-down signature of p has nonnegative partial sums with a maximal value <= 3.

Table of values

n a(n)
0 1
1 1
2 1
3 3
4 9
5 44
6 219
7 1445
8 9985
9 82741
10 728311
11 7283418
12 77655753
13 911793737
14 11395412415
15 153867507695
16 2202984651649
17 33654697818232
18 542738828304115
19 9258768392128641
20 166006249865713377
21 3128678609433086381
22 61725044306956275015
23 1273822982167765885166

List of values

[1, 1, 1, 3, 9, 44, 219, 1445, 9985, 82741, 728311, 7283418, 77655753, 911793737, 11395412415, 153867507695, 2202984651649, 33654697818232, 542738828304115, 9258768392128641, 166006249865713377, 3128678609433086381, 61725044306956275015, 1273822982167765885166]

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

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