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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.

A068911 Number of n-step walks (each step +-1 starting from 0) which are never more than 2 or less than -2.

Table of values

n a(n)
0 1
1 2
2 4
3 6
4 12
5 18
6 36
7 54
8 108
9 162
10 324
11 486
12 972
13 1458
14 2916
15 4374
16 8748
17 13122
18 26244
19 39366
20 78732
21 118098
22 236196
23 354294
24 708588
25 1062882
26 2125764
27 3188646
28 6377292
29 9565938
30 19131876
31 28697814
32 57395628
33 86093442
34 172186884
35 258280326
36 516560652

List of values

[1, 2, 4, 6, 12, 18, 36, 54, 108, 162, 324, 486, 972, 1458, 2916, 4374, 8748, 13122, 26244, 39366, 78732, 118098, 236196, 354294, 708588, 1062882, 2125764, 3188646, 6377292, 9565938, 19131876, 28697814, 57395628, 86093442, 172186884, 258280326, 516560652]

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

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