A121080 - cp's OEIS frontend

A121080 a(n) = Sum_{i=0..n} C(n,i)^2i!4^i + (1-2^n)2^(n-1)n!.

n	a(n)
0	1
1	4
2	37
3	541
4	10625
5	258661
6	7464625
7	248318309
8	9339986689
9	391569431365
10	18095180332721
11	913513359466885
12	50008961524486849
13	2950209091316054309
14	186558089772409191985
15	12587159519294553302821
16	902488447534988078746625
17	68518909362619336345906309

[1, 4, 37, 541, 10625, 258661, 7464625, 248318309, 9339986689, 391569431365, 18095180332721, 913513359466885, 50008961524486849, 2950209091316054309, 186558089772409191985, 12587159519294553302821, 902488447534988078746625, 68518909362619336345906309]

cp's OEIS Frontend

A121080 a(n) = Sum_{i=0..n} C(n,i)^2i!4^i + (1-2^n)2^(n-1)n!.

Table of values

List of values

cp's OEIS Frontend

A121080 a(n) = Sum_{i=0..n} C(n,i)^2*i!*4^i + (1-2^n)*2^(n-1)*n!.

Table of values

List of values

A121080 a(n) = Sum_{i=0..n} C(n,i)^2i!4^i + (1-2^n)2^(n-1)n!.