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.

A332840 Number of fixed-point free involutions in a fixed Sylow 2-subgroup of the symmetric group of degree 2n.

Table of values

n a(n)
0 1
1 1
2 3
3 3
4 17
5 17
6 51
7 51
8 417
9 417
10 1251
11 1251
12 7089
13 7089
14 21267
15 21267
16 206657
17 206657
18 619971
19 619971
20 3513169
21 3513169
22 10539507
23 10539507
24 86175969
25 86175969
26 258527907
27 258527907
28 1464991473
29 1464991473
30 4394974419
31 4394974419
32 44854599297
33 44854599297
34 134563797891

List of values

[1, 1, 3, 3, 17, 17, 51, 51, 417, 417, 1251, 1251, 7089, 7089, 21267, 21267, 206657, 206657, 619971, 619971, 3513169, 3513169, 10539507, 10539507, 86175969, 86175969, 258527907, 258527907, 1464991473, 1464991473, 4394974419, 4394974419, 44854599297, 44854599297, 134563797891]

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

Content is available under The OEIS End-User License Agreement.