A295371 - cp's OEIS frontend

A295371 a(n) = (1/(2n))Sum_{k=0..n-1} C(n-1, k)C(n+k, k)C(2k, k)(k+2)*(-3)^(n-1-k).

n	a(n)
1	1
2	3
3	19
4	127
5	921
6	6921
7	53523
8	422199
9	3382417
10	27429043
11	224636259
12	1854761437
13	15419579761
14	128941830993
15	1083686483259
16	9147887134119
17	77520233226537
18	659167237928691
19	5622149927918763
20	48083938099637247

[1, 3, 19, 127, 921, 6921, 53523, 422199, 3382417, 27429043, 224636259, 1854761437, 15419579761, 128941830993, 1083686483259, 9147887134119, 77520233226537, 659167237928691, 5622149927918763, 48083938099637247]

cp's OEIS Frontend

A295371 a(n) = (1/(2n))Sum_{k=0..n-1} C(n-1, k)C(n+k, k)C(2k, k)(k+2)*(-3)^(n-1-k).

Table of values

List of values

cp's OEIS Frontend

A295371 a(n) = (1/(2n))*Sum_{k=0..n-1} C(n-1, k)*C(n+k, k)*C(2k, k)*(k+2)*(-3)^(n-1-k).

Table of values

List of values

A295371 a(n) = (1/(2n))Sum_{k=0..n-1} C(n-1, k)C(n+k, k)C(2k, k)(k+2)*(-3)^(n-1-k).