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.

A006902 a(n) = (2n)! * Sum_{k=0..n} (-1)^k * binomial(n,k) / (n+k)!.

Table of values

n a(n)
0 1
1 1
2 5
3 47
4 641
5 11389
6 248749
7 6439075
8 192621953
9 6536413529
10 248040482741
11 10407123510871
12 478360626529345
13 23903857657114837
14 1290205338991689821
15 74803882225482661259
16 4636427218380366565889
17 305927317398343461908785
18 21410426012751471702223333

List of values

[1, 1, 5, 47, 641, 11389, 248749, 6439075, 192621953, 6536413529, 248040482741, 10407123510871, 478360626529345, 23903857657114837, 1290205338991689821, 74803882225482661259, 4636427218380366565889, 305927317398343461908785, 21410426012751471702223333]