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.

A348618 a(n) = (1+(-1)^n)/2*4^n*(C((3*n)/2-1,n))+(1-(-1)^n)/2*((C((3*n-1)/2,n))*(C(3*n-1,(3*n-1)/2)))/(C(n-1,(n-1)/2)).

Table of values

n a(n)
0 1
1 2
2 16
3 140
4 1280
5 12012
6 114688
7 1108536
8 10813440
9 106234700
10 1049624576
11 10418726760
12 103817412608
13 1037865473400
14 10404558274560
15 104557533120240
16 1052941297385472
17 10623352887172620
18 107358720517734400
19 1086563988284497800
20 11011614449734778880

List of values

[1, 2, 16, 140, 1280, 12012, 114688, 1108536, 10813440, 106234700, 1049624576, 10418726760, 103817412608, 1037865473400, 10404558274560, 104557533120240, 1052941297385472, 10623352887172620, 107358720517734400, 1086563988284497800, 11011614449734778880]