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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.

A371771 a(n) = Sum_{k=0..floor(n/3)} binomial(4*n-3*k-1,n-3*k).

Table of values

n a(n)
0 1
1 3
2 21
3 166
4 1377
5 11748
6 102088
7 898677
8 7987305
9 71517307
10 644134026
11 5829345492
12 52964836184
13 482846377185
14 4414405051413
15 40458397722306
16 371605426607673
17 3419639400458316
18 31521758873514301
19 291000881055737811
20 2690082750919841442

List of values

[1, 3, 21, 166, 1377, 11748, 102088, 898677, 7987305, 71517307, 644134026, 5829345492, 52964836184, 482846377185, 4414405051413, 40458397722306, 371605426607673, 3419639400458316, 31521758873514301, 291000881055737811, 2690082750919841442]

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

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