cp's OEIS Frontend

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.

A099786 a(n) = Sum_{k=0..floor(n/4)} C(n-k,3*k)*3^(n-4*k).

Table of values

n a(n)
0 1
1 3
2 9
3 27
4 82
5 255
6 819
7 2727
8 9397
9 33312
10 120537
11 441855
12 1631017
13 6036879
14 22345074
15 82589247
16 304612975
17 1120960983
18 4116353265
19 15088372416
20 55224373105
21 201895801851
22 737506551321
23 2692518758163
24 9826402960882

List of values

[1, 3, 9, 27, 82, 255, 819, 2727, 9397, 33312, 120537, 441855, 1631017, 6036879, 22345074, 82589247, 304612975, 1120960983, 4116353265, 15088372416, 55224373105, 201895801851, 737506551321, 2692518758163, 9826402960882]

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

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