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.

A293653 Young urn sequence (number of possible evolutions in n steps of the "Young" Pólya urn).

Table of values

n a(n)
0 1
1 2
2 6
3 30
4 180
5 1440
6 12960
7 142560
8 1710720
9 23950080
10 359251200
11 6107270400
12 109930867200
13 2198617344000
14 46170964224000
15 1061932177152000
16 25486372251648000
17 662645678542848000
18 17891433320656896000
19 518851566299049984000
20 15565546988971499520000
21 498097503647087984640000

List of values

[1, 2, 6, 30, 180, 1440, 12960, 142560, 1710720, 23950080, 359251200, 6107270400, 109930867200, 2198617344000, 46170964224000, 1061932177152000, 25486372251648000, 662645678542848000, 17891433320656896000, 518851566299049984000, 15565546988971499520000, 498097503647087984640000]

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

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