A371873 - cp's OEIS frontend

A371873 a(n) = Sum_{k=0..floor(n/3)} binomial(2n+1,n-3k).

n	a(n)
0	1
1	3
2	10
3	36
4	135
5	517
6	2003
7	7815
8	30634
9	120480
10	475002
11	1876294
12	7422676
13	29400192
14	116567356
15	462561572
16	1836843591
17	7298613997
18	29016050831
19	115408159467
20	459209330821
21	1827849895817
22	7277945888781
23	28986847296997
24	115479393316211
25	460159673245743

[1, 3, 10, 36, 135, 517, 2003, 7815, 30634, 120480, 475002, 1876294, 7422676, 29400192, 116567356, 462561572, 1836843591, 7298613997, 29016050831, 115408159467, 459209330821, 1827849895817, 7277945888781, 28986847296997, 115479393316211, 460159673245743]

cp's OEIS Frontend

A371873 a(n) = Sum_{k=0..floor(n/3)} binomial(2n+1,n-3k).

Table of values

List of values

cp's OEIS Frontend

A371873 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n+1,n-3*k).

Table of values

List of values

A371873 a(n) = Sum_{k=0..floor(n/3)} binomial(2n+1,n-3k).