A371820 - cp's OEIS frontend

A371820 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(2n+2,n-3k).

n	a(n)
0	1
1	4
2	15
3	55
4	200
5	726
6	2640
7	9636
8	35343
9	130339
10	483395
11	1802901
12	6760781
13	25482643
14	96506229
15	367077447
16	1401772536
17	5372120718
18	20653929804
19	79634421312
20	307826528346
21	1192608522258
22	4629875048634
23	18006340509702
24	70142823370656
25	273633773330844

[1, 4, 15, 55, 200, 726, 2640, 9636, 35343, 130339, 483395, 1802901, 6760781, 25482643, 96506229, 367077447, 1401772536, 5372120718, 20653929804, 79634421312, 307826528346, 1192608522258, 4629875048634, 18006340509702, 70142823370656, 273633773330844]

cp's OEIS Frontend

A371820 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(2n+2,n-3k).

Table of values

List of values

cp's OEIS Frontend

A371820 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(2*n+2,n-3*k).

Table of values

List of values

A371820 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(2n+2,n-3k).