A222807 - OEIS

A222807 as a simple table

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	0
10	0
11	0
12	0
13	0
14	0
15	4
16	10
17	30
18	66
19	144
20	314
21	692
22	1452
23	3046
24	6388
25	13298
26	27274
27	56164
28	113672
29	231892
30	470984
31	950178
32	1912700
33	3868034
34	7772172
35	15651674
36	31464544
37	63154106
38	126603428
39	254088618
40	508541874
41	1018817124

[0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,10,30,66,144,314, 692,1452,3046,6388,13298,27274,56164,113672, 231892,470984,950178,1912700,3868034,7772172, 15651674,31464544,63154106,126603428,254088618, 508541874,1018817124]