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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.

A371754 a(n) = Sum_{k=0..floor(n/3)} binomial(3*n-2*k,n-3*k).

Table of values

n a(n)
0 1
1 3
2 15
3 85
4 505
5 3081
6 19125
7 120173
8 761995
9 4865697
10 31244029
11 201544551
12 1305039209
13 8477521051
14 55221311565
15 360559717807
16 2359123470971
17 15463951609491
18 101530816122729
19 667587477393509
20 4395294402200983
21 28972295880583861
22 191181607835416543

List of values

[1, 3, 15, 85, 505, 3081, 19125, 120173, 761995, 4865697, 31244029, 201544551, 1305039209, 8477521051, 55221311565, 360559717807, 2359123470971, 15463951609491, 101530816122729, 667587477393509, 4395294402200983, 28972295880583861, 191181607835416543]

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

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