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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.

A383525 a(n) = Sum_{k=0..floor(n/3)} binomial(n,k)^2 * binomial(n-2*k,k).

Table of values

n a(n)
0 1
1 1
2 1
3 10
4 33
5 76
6 370
7 1569
8 5089
9 20584
10 88776
11 336865
12 1336434
13 5639869
14 22824789
15 92230285
16 384930529
17 1595575648
18 6570596764
19 27418859721
20 114736740808
21 478594009281
22 2005907811469
23 8437974722463
24 35480386059826
25 149466347150701
26 631299305598625
27 2668522402478179

List of values

[1, 1, 1, 10, 33, 76, 370, 1569, 5089, 20584, 88776, 336865, 1336434, 5639869, 22824789, 92230285, 384930529, 1595575648, 6570596764, 27418859721, 114736740808, 478594009281, 2005907811469, 8437974722463, 35480386059826, 149466347150701, 631299305598625, 2668522402478179]

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

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