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.

A002861 Number of connected functions (or mapping patterns) on n unlabeled points, or number of rings and branches with n edges.

Table of values

n a(n)
1 1
2 2
3 4
4 9
5 20
6 51
7 125
8 329
9 862
10 2311
11 6217
12 16949
13 46350
14 127714
15 353272
16 981753
17 2737539
18 7659789
19 21492286
20 60466130
21 170510030
22 481867683
23 1364424829
24 3870373826
25 10996890237
26 31293083540
27 89173833915
28 254445242754
29 726907585652
30 2079012341822

List of values

[1, 2, 4, 9, 20, 51, 125, 329, 862, 2311, 6217, 16949, 46350, 127714, 353272, 981753, 2737539, 7659789, 21492286, 60466130, 170510030, 481867683, 1364424829, 3870373826, 10996890237, 31293083540, 89173833915, 254445242754, 726907585652, 2079012341822]