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.

A208124 a(1)=2, a(n) = (4n/3)*(2n-1)!! (see A001147) for n>1.

Table of values

n a(n)
1 2
2 8
3 60
4 560
5 6300
6 83160
7 1261260
8 21621600
9 413513100
10 8729721000
11 201656555100
12 5059746291600
13 137034795397500
14 3984550204635000
15 123805667072587500
16 4093840724533560000
17 143540290403957947500
18 5319434291440794525000
19 207753461493493252837500
20 8528826313943407221750000

List of values

[2, 8, 60, 560, 6300, 83160, 1261260, 21621600, 413513100, 8729721000, 201656555100, 5059746291600, 137034795397500, 3984550204635000, 123805667072587500, 4093840724533560000, 143540290403957947500, 5319434291440794525000, 207753461493493252837500, 8528826313943407221750000]

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

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