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.

A227941 Number of 1 up, 3 down, 5 up, 7 down, ... permutations of [n].

Table of values

n a(n)
0 1
1 1
2 1
3 2
4 3
5 4
6 19
7 55
8 125
9 245
10 434
11 4060
12 21186
13 81212
14 254813
15 692678
16 1688555
17 3776432
18 60101767
19 511650887
20 3089821383
21 14824989723
22 60057570858
23 213302293918
24 681247718668
25 1992449334436
26 5409214694961
27 132273848506202
28 1692162553490943

List of values

[1, 1, 1, 2, 3, 4, 19, 55, 125, 245, 434, 4060, 21186, 81212, 254813, 692678, 1688555, 3776432, 60101767, 511650887, 3089821383, 14824989723, 60057570858, 213302293918, 681247718668, 1992449334436, 5409214694961, 132273848506202, 1692162553490943]