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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.

A371871 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-3*k-2,n-3*k).

Table of values

n a(n)
0 1
1 0
2 1
3 5
4 18
5 66
6 246
7 924
8 3493
9 13277
10 50697
11 194327
12 747319
13 2882061
14 11142027
15 43167573
16 167561586
17 651513594
18 2537041938
19 9892847952
20 38623197264
21 150959213886
22 590626854072
23 2312979822738
24 9065733950526
25 35561306875380
26 139595183125750

List of values

[1, 0, 1, 5, 18, 66, 246, 924, 3493, 13277, 50697, 194327, 747319, 2882061, 11142027, 43167573, 167561586, 651513594, 2537041938, 9892847952, 38623197264, 150959213886, 590626854072, 2312979822738, 9065733950526, 35561306875380, 139595183125750]

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

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