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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.

A386565 a(n) = Sum_{k=0..n-1} binomial(4*k-1,k) * binomial(4*n-4*k,n-k-1).

Table of values

n a(n)
0 0
1 1
2 11
3 111
4 1091
5 10596
6 102237
7 982458
8 9415539
9 90063180
10 860278156
11 8208539351
12 78258171957
13 745595635084
14 7099714918062
15 67574576298276
16 642927956583123
17 6115089154367484
18 58146652079312580
19 552769690436583532
20 5253812277363417836
21 49925987913040522128

List of values

[0, 1, 11, 111, 1091, 10596, 102237, 982458, 9415539, 90063180, 860278156, 8208539351, 78258171957, 745595635084, 7099714918062, 67574576298276, 642927956583123, 6115089154367484, 58146652079312580, 552769690436583532, 5253812277363417836, 49925987913040522128]

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

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