A371817 - cp's OEIS frontend

A371817 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(4n-3k-1,n-3*k).

n	a(n)
0	1
1	3
2	21
3	164
4	1353
5	11508
6	99808
7	877425
8	7790745
9	69704921
10	627438606
11	5675535000
12	51546958296
13	469764721533
14	4293594852225
15	39341599326304
16	361271345551257
17	3323924166943410
18	30634431485945569
19	282767849049333909
20	2613630939017216898

[1, 3, 21, 164, 1353, 11508, 99808, 877425, 7790745, 69704921, 627438606, 5675535000, 51546958296, 469764721533, 4293594852225, 39341599326304, 361271345551257, 3323924166943410, 30634431485945569, 282767849049333909, 2613630939017216898]

cp's OEIS Frontend

A371817 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(4n-3k-1,n-3*k).

Table of values

List of values

cp's OEIS Frontend

A371817 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(4*n-3*k-1,n-3*k).

Table of values

List of values

A371817 a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(4n-3k-1,n-3*k).