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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.

A174080 Number of permutations of length n with no consecutive triples i,i+d,i+2d for all d>0.

Table of values

n a(n)
0 1
1 1
2 2
3 5
4 21
5 100
6 597
7 4113
8 32842
9 292379
10 2925367
11 31983248
12 383514347
13 4966286235
14 69508102006
15 1039315462467
16 16627618496319
17 282023014602100
18 5075216962675445
19 96263599713301975
20 1925002914124917950

List of values

[1, 1, 2, 5, 21, 100, 597, 4113, 32842, 292379, 2925367, 31983248, 383514347, 4966286235, 69508102006, 1039315462467, 16627618496319, 282023014602100, 5075216962675445, 96263599713301975, 1925002914124917950]

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

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