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.

A063886 Number of n-step walks on a line starting from the origin but not returning to it.

Table of values

n a(n)
0 1
1 2
2 2
3 4
4 6
5 12
6 20
7 40
8 70
9 140
10 252
11 504
12 924
13 1848
14 3432
15 6864
16 12870
17 25740
18 48620
19 97240
20 184756
21 369512
22 705432
23 1410864
24 2704156
25 5408312
26 10400600
27 20801200
28 40116600
29 80233200
30 155117520
31 310235040
32 601080390
33 1202160780
34 2333606220
35 4667212440

List of values

[1, 2, 2, 4, 6, 12, 20, 40, 70, 140, 252, 504, 924, 1848, 3432, 6864, 12870, 25740, 48620, 97240, 184756, 369512, 705432, 1410864, 2704156, 5408312, 10400600, 20801200, 40116600, 80233200, 155117520, 310235040, 601080390, 1202160780, 2333606220, 4667212440]

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

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