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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.

A100131 a(n) = Sum_{k=0..floor(n/4)} binomial(n-2k, 2k)*2^(n-4k).

Table of values

n a(n)
0 1
1 2
2 4
3 8
4 17
5 38
6 88
7 208
8 497
9 1194
10 2876
11 6936
12 16737
13 40398
14 97520
15 235424
16 568353
17 1372114
18 3312564
19 7997224
20 19306993
21 46611190
22 112529352
23 271669872
24 655869073
25 1583407994
26 3822685036
27 9228778040
28 22280241089
29 53789260190
30 129858761440
31 313506783040

List of values

[1, 2, 4, 8, 17, 38, 88, 208, 497, 1194, 2876, 6936, 16737, 40398, 97520, 235424, 568353, 1372114, 3312564, 7997224, 19306993, 46611190, 112529352, 271669872, 655869073, 1583407994, 3822685036, 9228778040, 22280241089, 53789260190, 129858761440, 313506783040]

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

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