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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.

A099579 a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, k-1) * 3^(k-1).

Table of values

n a(n)
0 0
1 0
2 1
3 1
4 7
5 10
6 40
7 70
8 217
9 427
10 1159
11 2440
12 6160
13 13480
14 32689
15 73129
16 173383
17 392770
18 919480
19 2097790
20 4875913
21 11169283
22 25856071
23 59363920
24 137109280
25 315201040
26 727060321
27 1672663441
28 3855438727
29 8873429050
30 20444528200

List of values

[0, 0, 1, 1, 7, 10, 40, 70, 217, 427, 1159, 2440, 6160, 13480, 32689, 73129, 173383, 392770, 919480, 2097790, 4875913, 11169283, 25856071, 59363920, 137109280, 315201040, 727060321, 1672663441, 3855438727, 8873429050, 20444528200]

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

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