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.

A240957 G.f.: Sum_{n>=0} n^n * x^n * (3 + 2*n*x)^n / ((1 + n*x)*(1 + 2*n*x))^(n+1).

Table of values

n a(n)
0 1
1 3
2 20
3 234
4 3944
5 86400
6 2324160
7 74062800
8 2726970624
9 113893395840
10 5319595814400
11 274730601277440
12 15544557784673280
13 956232958853652480
14 63540675378122342400
15 4535620918350762240000
16 346127227962539155292160
17 28120835253815298895380480
18 2423309442415144546546483200

List of values

[1, 3, 20, 234, 3944, 86400, 2324160, 74062800, 2726970624, 113893395840, 5319595814400, 274730601277440, 15544557784673280, 956232958853652480, 63540675378122342400, 4535620918350762240000, 346127227962539155292160, 28120835253815298895380480, 2423309442415144546546483200]