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.

A112091 Number of idempotent order-preserving partial transformations (of an n-element chain).

Table of values

n a(n)
0 1
1 2
2 6
3 21
4 76
5 276
6 1001
7 3626
8 13126
9 47501
10 171876
11 621876
12 2250001
13 8140626
14 29453126
15 106562501
16 385546876
17 1394921876
18 5046875001
19 18259765626
20 66064453126
21 239023437501
22 864794921876
23 3128857421876
24 11320312500001

List of values

[1, 2, 6, 21, 76, 276, 1001, 3626, 13126, 47501, 171876, 621876, 2250001, 8140626, 29453126, 106562501, 385546876, 1394921876, 5046875001, 18259765626, 66064453126, 239023437501, 864794921876, 3128857421876, 11320312500001]

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

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