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.

A221625 Number of 3Xn arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row.

Table of values

n a(n)
1 1
2 4
3 112
4 6120
5 738150
6 148700748
7 49096652080
8 24099422236160
9 17023170538890750
10 16517958827528755300
11 21433818529290626472948
12 36180795747764068402865136
13 77856103174007703918070147632

List of values

[1, 4, 112, 6120, 738150, 148700748, 49096652080, 24099422236160, 17023170538890750, 16517958827528755300, 21433818529290626472948, 36180795747764068402865136, 77856103174007703918070147632]

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

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