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.

A129777 Number of freely-braided hexagon-avoiding permutations in S_n; the freely-braided hexagon-avoiding permutations are those that avoid 3421, 4231, 4312, 4321, 46718235, 46781235, 56718234 and 56781234.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 20
5 71
6 260
7 971
8 3670
9 13968
10 53369
11 204352
12 783408
13 3005284
14 11533014
15 44267854
16 169935041
17 652385639
18 2504613713
19 9615798516
20 36917689075
21 141737959416
22 544175811783
23 2089262741393
24 8021347093432
25 30796530585417
26 118237818141689
27 453953210838465

List of values

[1, 1, 2, 6, 20, 71, 260, 971, 3670, 13968, 53369, 204352, 783408, 3005284, 11533014, 44267854, 169935041, 652385639, 2504613713, 9615798516, 36917689075, 141737959416, 544175811783, 2089262741393, 8021347093432, 30796530585417, 118237818141689, 453953210838465]

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

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