A270490 - cp's OEIS frontend

A270490 a(n) = Sum_{i=0..(n+1)/2} binomial(2i+1,i)binomial(2n-2i,n)/(2*i+1).

n	a(n)
0	1
1	2
2	7
3	24
4	87
5	320
6	1195
7	4504
8	17102
9	65304
10	250501
11	964480
12	3724996
13	14424504
14	55983091
15	217702880
16	848042197
17	3308490496
18	12924954514
19	50553798696
20	197948515868
21	775853655760
22	3043672637457
23	11950142769664
24	46954356540812

[1, 2, 7, 24, 87, 320, 1195, 4504, 17102, 65304, 250501, 964480, 3724996, 14424504, 55983091, 217702880, 848042197, 3308490496, 12924954514, 50553798696, 197948515868, 775853655760, 3043672637457, 11950142769664, 46954356540812]

cp's OEIS Frontend

A270490 a(n) = Sum_{i=0..(n+1)/2} binomial(2i+1,i)binomial(2n-2i,n)/(2*i+1).

Table of values

List of values

cp's OEIS Frontend

A270490 a(n) = Sum_{i=0..(n+1)/2} binomial(2*i+1,i)*binomial(2*n-2*i,n)/(2*i+1).

Table of values

List of values

A270490 a(n) = Sum_{i=0..(n+1)/2} binomial(2i+1,i)binomial(2n-2i,n)/(2*i+1).