A126965 - cp's OEIS frontend

A126965 a(n) = (2n)!(2n-1)/(2^nn!).

n	a(n)
0	-1
1	1
2	9
3	75
4	735
5	8505
6	114345
7	1756755
8	30405375
9	585810225
10	12439852425
11	288735522075
12	7273385294175
13	197646339515625
14	5763367260275625
15	179518217255251875
16	5948862302837829375
17	208977775735174070625
18	7757508341684492015625
19	303429397707601987696875

[-1, 1, 9, 75, 735, 8505, 114345, 1756755, 30405375, 585810225, 12439852425, 288735522075, 7273385294175, 197646339515625, 5763367260275625, 179518217255251875, 5948862302837829375, 208977775735174070625, 7757508341684492015625, 303429397707601987696875]

cp's OEIS Frontend

A126965 a(n) = (2n)!(2n-1)/(2^nn!).

Table of values

List of values

cp's OEIS Frontend

A126965 a(n) = (2*n)!*(2*n-1)/(2^n*n!).

Table of values

List of values

A126965 a(n) = (2n)!(2n-1)/(2^nn!).