A378069 - cp's OEIS frontend

A378069 a(n) = Sum_{k=0..n} binomial(n, floor(k/2 - 1/2)) * binomial(n, ceiling(k/2 - 1/2)).

n	a(n)
0	0
1	1
2	3
3	13
4	45
5	181
6	658
7	2605
8	9705
9	38251
10	144606
11	569317
12	2173262
13	8556822
14	32890068
15	129565485
16	500583105
17	1973295775
18	7654363750
19	30194784763
20	117497078842
21	463820452602
22	1809540528588
23	7147843461733
24	27946421773270
25	110458073192026
26	432648616232028

[0, 1, 3, 13, 45, 181, 658, 2605, 9705, 38251, 144606, 569317, 2173262, 8556822, 32890068, 129565485, 500583105, 1973295775, 7654363750, 30194784763, 117497078842, 463820452602, 1809540528588, 7147843461733, 27946421773270, 110458073192026, 432648616232028]

cp's OEIS Frontend

A378069 a(n) = Sum_{k=0..n} binomial(n, floor(k/2 - 1/2)) * binomial(n, ceiling(k/2 - 1/2)).

Table of values

List of values