A337155 - cp's OEIS frontend

A337155 a(n) = 5^n * (n!)^2 * Sum_{k=0..n} 1 / ((-5)^k * (k!)^2).

n	a(n)
0	1
1	4
2	81
3	3644
4	291521
5	36440124
6	6559222321
7	1607009468644
8	514243029966081
9	208268427136262804
10	104134213568131402001
11	63001199208719498210604
12	45360863430278038711634881
13	38329929598584942711331474444
14	37563331006613243857104844955121
15	42258747382439899339242950574511124

[1, 4, 81, 3644, 291521, 36440124, 6559222321, 1607009468644, 514243029966081, 208268427136262804, 104134213568131402001, 63001199208719498210604, 45360863430278038711634881, 38329929598584942711331474444, 37563331006613243857104844955121, 42258747382439899339242950574511124]

cp's OEIS Frontend

A337155 a(n) = 5^n * (n!)^2 * Sum_{k=0..n} 1 / ((-5)^k * (k!)^2).

Table of values

List of values