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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.

A100139 a(n) = Sum_{k=0..floor(n/6)} C(n-3k,3k) * 3^k * 2^(n-6k).

Table of values

n a(n)
0 1
1 2
2 4
3 8
4 16
5 32
6 67
7 152
8 376
9 992
10 2704
11 7424
12 20233
13 54398
14 144112
15 376736
16 974368
17 2500544
18 6385435
19 16264220
20 41396788
21 105423776
22 268818064
23 686499008
24 1755723793
25 4495691834
26 11521647916
27 29543647160
28 75774096832
29 194353495424

List of values

[1, 2, 4, 8, 16, 32, 67, 152, 376, 992, 2704, 7424, 20233, 54398, 144112, 376736, 974368, 2500544, 6385435, 16264220, 41396788, 105423776, 268818064, 686499008, 1755723793, 4495691834, 11521647916, 29543647160, 75774096832, 194353495424]

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

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