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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.

A216584 a(n) = A002426(n)*A000984(n); product of central trinomial coefficients and central binomial coefficients.

Table of values

n a(n)
0 1
1 2
2 18
3 140
4 1330
5 12852
6 130284
7 1348776
8 14247090
9 152618180
10 1654120468
11 18096447096
12 199536967084
13 2214714164600
14 24720932068200
15 277289164574640
16 3123590583844530
17 35318969120870820
18 400692715550057700
19 4559427798654821400
20 52020436064931914580

List of values

[1, 2, 18, 140, 1330, 12852, 130284, 1348776, 14247090, 152618180, 1654120468, 18096447096, 199536967084, 2214714164600, 24720932068200, 277289164574640, 3123590583844530, 35318969120870820, 400692715550057700, 4559427798654821400, 52020436064931914580]

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

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