A346224 - cp's OEIS frontend

A346224 a(n) = (n!)^2 * Sum_{k=0..floor(n/2)} 1 / ((n-2k)! 4^k * k!).

n	a(n)
0	1
1	1
2	3
3	15
4	114
5	1170
6	15570
7	256410
8	5103000
9	119773080
10	3264445800
11	101784097800
12	3591396824400
13	141958074258000
14	6236035482877200
15	302218901402418000
16	16060366291617648000
17	930654556409161584000
18	58524794739862410960000
19	3976525824684785163792000

[1, 1, 3, 15, 114, 1170, 15570, 256410, 5103000, 119773080, 3264445800, 101784097800, 3591396824400, 141958074258000, 6236035482877200, 302218901402418000, 16060366291617648000, 930654556409161584000, 58524794739862410960000, 3976525824684785163792000]

cp's OEIS Frontend

A346224 a(n) = (n!)^2 * Sum_{k=0..floor(n/2)} 1 / ((n-2k)! 4^k * k!).

Table of values

List of values

cp's OEIS Frontend

A346224 a(n) = (n!)^2 * Sum_{k=0..floor(n/2)} 1 / ((n-2*k)! * 4^k * k!).

Table of values

List of values

A346224 a(n) = (n!)^2 * Sum_{k=0..floor(n/2)} 1 / ((n-2k)! 4^k * k!).