A336807 - cp's OEIS frontend

A336807 a(n) = (n!)^2 * Sum_{k=0..n} 4^(n-k) / (k!)^2.

n	a(n)
0	1
1	5
2	81
3	2917
4	186689
5	18668901
6	2688321745
7	526911062021
8	134889231877377
9	43704111128270149
10	17481644451308059601
11	8461115914433100846885
12	4873602766713466087805761
13	3294555470298303075356694437
14	2582931488713869611079648438609
15	2324638339842482649971683594748101

[1, 5, 81, 2917, 186689, 18668901, 2688321745, 526911062021, 134889231877377, 43704111128270149, 17481644451308059601, 8461115914433100846885, 4873602766713466087805761, 3294555470298303075356694437, 2582931488713869611079648438609, 2324638339842482649971683594748101]

cp's OEIS Frontend

A336807 a(n) = (n!)^2 * Sum_{k=0..n} 4^(n-k) / (k!)^2.

Table of values

List of values