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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.

A339830 Number of bicolored trees on n unlabeled nodes such that black nodes are not adjacent to each other.

Table of values

n a(n)
0 1
1 2
2 2
3 4
4 10
5 26
6 75
7 234
8 768
9 2647
10 9466
11 34818
12 131149
13 503640
14 1965552
15 7777081
16 31138051
17 125961762
18 514189976
19 2115922969
20 8769932062
21 36584593158
22 153510347137
23 647564907923
24 2744951303121
25 11687358605310
26 49965976656637
27 214423520420723
28 923399052307921

List of values

[1, 2, 2, 4, 10, 26, 75, 234, 768, 2647, 9466, 34818, 131149, 503640, 1965552, 7777081, 31138051, 125961762, 514189976, 2115922969, 8769932062, 36584593158, 153510347137, 647564907923, 2744951303121, 11687358605310, 49965976656637, 214423520420723, 923399052307921]

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

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