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.

A272492 Number of ordered set partitions of [n] with nondecreasing block sizes and maximal block size equal to two.

Table of values

n a(n)
2 1
3 3
4 18
5 90
6 630
7 4410
8 37800
9 340200
10 3515400
11 38669400
12 471517200
13 6129723600
14 86497210800
15 1297458162000
16 20841060240000
17 354298024080000
18 6389869069584000
19 121407512322096000
20 2430526127309280000
21 51041048673494880000
22 1123451899297247520000

List of values

[1, 3, 18, 90, 630, 4410, 37800, 340200, 3515400, 38669400, 471517200, 6129723600, 86497210800, 1297458162000, 20841060240000, 354298024080000, 6389869069584000, 121407512322096000, 2430526127309280000, 51041048673494880000, 1123451899297247520000]

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

Content is available under The OEIS End-User License Agreement.