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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.

A351223 a(n) is the number of triangular arrays containing the first 3*(n - 1) positive integers arranged with number n on each side and having different set of the sets of the side integers.

Table of values

n a(n)
2 1
3 120
4 7560
5 369600
6 15765750
7 617512896
8 22813670880
9 807723671040
10 27686621927250
11 925166131890000
12 30286238493551040
13 974802747606105600
14 30933063577681246800
15 969808565876506272000
16 30090926129273230320000
17 925249170367839629537280
18 28225069296255264089522250

List of values

[1, 120, 7560, 369600, 15765750, 617512896, 22813670880, 807723671040, 27686621927250, 925166131890000, 30286238493551040, 974802747606105600, 30933063577681246800, 969808565876506272000, 30090926129273230320000, 925249170367839629537280, 28225069296255264089522250]

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

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