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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.

A188669 a(n) = ceiling(binomial(2*n-1,n-1)/n).

Table of values

n a(n)
1 1
2 2
3 4
4 9
5 26
6 77
7 246
8 805
9 2702
10 9238
11 32066
12 112674
13 400024
14 1432736
15 5170584
16 18783763
17 68635478
18 252087092
19 930138522
20 3446163221
21 12815663678
22 47820430994
23 178987624514
24 671825076732
25 2528212128756
26 9536894864387
27 36054433808299
28 136583760727865
29 518401146543812
30 1971076359414358
31 7506908923471954
32 28634752202227978

List of values

[1, 2, 4, 9, 26, 77, 246, 805, 2702, 9238, 32066, 112674, 400024, 1432736, 5170584, 18783763, 68635478, 252087092, 930138522, 3446163221, 12815663678, 47820430994, 178987624514, 671825076732, 2528212128756, 9536894864387, 36054433808299, 136583760727865, 518401146543812, 1971076359414358, 7506908923471954, 28634752202227978]

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

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