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.

A343975 a(0) = 1; a(n) = 3 * Sum_{k=1..n} binomial(n,k) * a(k-1).

Table of values

n a(n)
0 1
1 3
2 15
3 81
4 489
5 3237
6 23211
7 178707
8 1467051
9 12768345
10 117263829
11 1131901521
12 11444383251
13 120847326879
14 1329303053391
15 15197269729689
16 180211641841353
17 2212525627591533
18 28078380387448515
19 367782119667874083
20 4965441830591976339
21 69014083524412401873
22 986364827548578356421

List of values

[1, 3, 15, 81, 489, 3237, 23211, 178707, 1467051, 12768345, 117263829, 1131901521, 11444383251, 120847326879, 1329303053391, 15197269729689, 180211641841353, 2212525627591533, 28078380387448515, 367782119667874083, 4965441830591976339, 69014083524412401873, 986364827548578356421]

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

Content is available under The OEIS End-User License Agreement.