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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.

A371816 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(3*n-3*k-1,n-3*k).

Table of values

n a(n)
0 1
1 2
2 10
3 55
4 322
5 1947
6 12013
7 75154
8 474946
9 3024742
10 19381045
11 124797862
12 806875421
13 5234713031
14 34060165282
15 222174355575
16 1452425614146
17 9513309908589
18 62418283102246
19 410161124310550
20 2698932409666237
21 17781425199962255
22 117281204608676426

List of values

[1, 2, 10, 55, 322, 1947, 12013, 75154, 474946, 3024742, 19381045, 124797862, 806875421, 5234713031, 34060165282, 222174355575, 1452425614146, 9513309908589, 62418283102246, 410161124310550, 2698932409666237, 17781425199962255, 117281204608676426]

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

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