A336809 - cp's OEIS frontend

A336809 a(n) = (n!)^2 * Sum_{k=0..n} (k+1) / ((n-k)!)^2.

n	a(n)
0	1
1	3
2	21
3	271
4	5649
5	174051
6	7447573
7	422836191
8	30767443521
9	2792343036259
10	309252314731701
11	41051709426337743
12	6434479982900111761
13	1175819833620882461571
14	247785659825802622964469
15	59649892258930263778729951
16	16268290830606063971956320513

[1, 3, 21, 271, 5649, 174051, 7447573, 422836191, 30767443521, 2792343036259, 309252314731701, 41051709426337743, 6434479982900111761, 1175819833620882461571, 247785659825802622964469, 59649892258930263778729951, 16268290830606063971956320513]

cp's OEIS Frontend

A336809 a(n) = (n!)^2 * Sum_{k=0..n} (k+1) / ((n-k)!)^2.

Table of values

List of values