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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.

A109092 Number of hierarchical orderings for n labeled elements with 2 possible classes A and B for levels l>=2. Labeled analog of A104460.

Table of values

n a(n)
1 1
2 6
3 53
4 619
5 8972
6 155067
7 3109269
8 70893872
9 1810283331
10 51151579619
11 1583934062306
12 53322541667501
13 1938521128765093
14 75673000809822670
15 3156390306304019025
16 140076451219218605087
17 6589244960448222899044
18 327461842184597424792623
19 17141751726301435708168665

List of values

[1, 6, 53, 619, 8972, 155067, 3109269, 70893872, 1810283331, 51151579619, 1583934062306, 53322541667501, 1938521128765093, 75673000809822670, 3156390306304019025, 140076451219218605087, 6589244960448222899044, 327461842184597424792623, 17141751726301435708168665]

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

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