A380121 - cp's OEIS frontend

A380121 a(n) = C(n, Q(n+3, 4)-1)C(n, Q(n+1, 4)) + C(n, Q(3n+1, 4))C(n, Q(3n+3, 4)) where C = binomial and Q(x, y) = floor(x/y).

n	a(n)
0	1
1	2
2	3
3	6
4	20
5	50
6	126
7	294
8	1008
9	2592
10	7425
11	18150
12	62920
13	163592
14	496860
15	1242150
16	4331600
17	11328800
18	35581680
19	90140256
20	315490896
21	828163602
22	2658338298
23	6793531206
24	23836951600
25	62728820000
26	204451146900
27	525731520600
28	1848025951200
29	4872068416800
30	16059866355000

[1, 2, 3, 6, 20, 50, 126, 294, 1008, 2592, 7425, 18150, 62920, 163592, 496860, 1242150, 4331600, 11328800, 35581680, 90140256, 315490896, 828163602, 2658338298, 6793531206, 23836951600, 62728820000, 204451146900, 525731520600, 1848025951200, 4872068416800, 16059866355000]

cp's OEIS Frontend

A380121 a(n) = C(n, Q(n+3, 4)-1)C(n, Q(n+1, 4)) + C(n, Q(3n+1, 4))C(n, Q(3n+3, 4)) where C = binomial and Q(x, y) = floor(x/y).

Table of values

List of values

cp's OEIS Frontend

A380121 a(n) = C(n, Q(n+3, 4)-1)*C(n, Q(n+1, 4)) + C(n, Q(3*n+1, 4))*C(n, Q(3*n+3, 4)) where C = binomial and Q(x, y) = floor(x/y).

Table of values

List of values

A380121 a(n) = C(n, Q(n+3, 4)-1)C(n, Q(n+1, 4)) + C(n, Q(3n+1, 4))C(n, Q(3n+3, 4)) where C = binomial and Q(x, y) = floor(x/y).