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.

A355089 Number of parity-alternating permutations of [n] avoiding the pattern 123.

Table of values

n a(n)
0 1
1 1
2 1
3 1
4 3
5 3
6 10
7 11
8 37
9 44
10 146
11 185
12 603
13 808
14 2576
15 3635
16 11294
17 16736
18 50545
19 78466
20 230012
21 373203
22 1061236
23 1795611
24 4953447
25 8721086
26 23350320
27 42691298
28 111013825
29 210379132
30 531720722

List of values

[1, 1, 1, 1, 3, 3, 10, 11, 37, 44, 146, 185, 603, 808, 2576, 3635, 11294, 16736, 50545, 78466, 230012, 373203, 1061236, 1795611, 4953447, 8721086, 23350320, 42691298, 111013825, 210379132, 531720722]