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.

A193778 Number of signed permutations of length 2n invariant under D and D'bar.

Table of values

n a(n)
0 1
1 2
2 8
3 32
4 160
5 832
6 4864
7 29696
8 195584
9 1341440
10 9723904
11 73105408
12 574062592
13 4657184768
14 39165624320
15 339133595648
16 3028204650496
17 27760959422464
18 261439835078656
19 2521668748574720
20 24912764963127296
21 251559029812232192
22 2595790316527157248

List of values

[1, 2, 8, 32, 160, 832, 4864, 29696, 195584, 1341440, 9723904, 73105408, 574062592, 4657184768, 39165624320, 339133595648, 3028204650496, 27760959422464, 261439835078656, 2521668748574720, 24912764963127296, 251559029812232192, 2595790316527157248]

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

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