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.

A217420 Number of rooted unlabeled trees where the root node has degree 2 and both branches are distinct.

Table of values

n a(n)
1 0
2 0
3 0
4 1
5 2
6 6
7 14
8 37
9 92
10 239
11 613
12 1607
13 4215
14 11185
15 29814
16 80070
17 216061
18 586218
19 1597292
20 4370721
21 12003163
22 33077327
23 91431425
24 253454781
25 704425087
26 1962537755
27 5479843060
28 15332668869
29 42983623237
30 120716987723
31 339595975795
32 956840683968

List of values

[0, 0, 0, 1, 2, 6, 14, 37, 92, 239, 613, 1607, 4215, 11185, 29814, 80070, 216061, 586218, 1597292, 4370721, 12003163, 33077327, 91431425, 253454781, 704425087, 1962537755, 5479843060, 15332668869, 42983623237, 120716987723, 339595975795, 956840683968]