A086905 - cp's OEIS frontend

A086905 a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(k,floor(k/2)).

n	a(n)
0	1
1	0
2	2
3	1
4	5
5	5
6	15
7	20
8	50
9	76
10	176
11	286
12	638
13	1078
14	2354
15	4081
16	8789
17	15521
18	33099
19	59279
20	125477
21	227239
22	478193
23	873885
24	1830271
25	3370029
26	7030571
27	13027729
28	27088871
29	50469889
30	104647631
31	195892564
32	405187826
33	761615284
34	1571990936

[1, 0, 2, 1, 5, 5, 15, 20, 50, 76, 176, 286, 638, 1078, 2354, 4081, 8789, 15521, 33099, 59279, 125477, 227239, 478193, 873885, 1830271, 3370029, 7030571, 13027729, 27088871, 50469889, 104647631, 195892564, 405187826, 761615284, 1571990936]

cp's OEIS Frontend

A086905 a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(k,floor(k/2)).

Table of values

List of values