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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.

A261681 a(n) = 2^n + binomial(n, floor(n/2)) - 1.

Table of values

n a(n)
0 1
1 2
2 5
3 10
4 21
5 41
6 83
7 162
8 325
9 637
10 1275
11 2509
12 5019
13 9907
14 19815
15 39202
16 78405
17 155381
18 310763
19 616665
20 1233331
21 2449867
22 4899735
23 9740685
24 19481371
25 38754731
26 77509463
27 154276027
28 308552055
29 614429671
30 1228859343
31 2448023842
32 4896047685
33 9756737701

List of values

[1, 2, 5, 10, 21, 41, 83, 162, 325, 637, 1275, 2509, 5019, 9907, 19815, 39202, 78405, 155381, 310763, 616665, 1233331, 2449867, 4899735, 9740685, 19481371, 38754731, 77509463, 154276027, 308552055, 614429671, 1228859343, 2448023842, 4896047685, 9756737701]

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

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