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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.

A383537 a(n) = Sum_{k=0..floor(n/3)} binomial(n+k,k)^2 * binomial(n-2*k,k).

Table of values

n a(n)
0 1
1 1
2 1
3 17
4 51
5 109
6 981
7 4209
8 12637
9 79351
10 393493
11 1454021
12 7686459
13 39697057
14 166999101
15 823144689
16 4241896917
17 19293138685
18 93151760599
19 473739765167
20 2252548154403
21 10877558634801
22 54682637188009
23 266304982300197
24 1295171619802551
25 6466091747859771

List of values

[1, 1, 1, 17, 51, 109, 981, 4209, 12637, 79351, 393493, 1454021, 7686459, 39697057, 166999101, 823144689, 4241896917, 19293138685, 93151760599, 473739765167, 2252548154403, 10877558634801, 54682637188009, 266304982300197, 1295171619802551, 6466091747859771]

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

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