A047765 - OEIS

A047765 as a simple table

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	2
7	0
8	2
9	0
10	7
11	0
12	12
13	0
14	29
15	0
16	55
17	0
18	143
19	0
20	271
21	0
22	728
23	0
24	1428
25	0
26	3873
27	0
28	7752
29	0
30	21318
31	0
32	43256
33	0
34	120175
35	0
36	246675
37	0
38	690678
39	0
40	1430715
41	0
42	4032015
43	0
44	8414610
45	0
46	23841480
47	0
48	50067108
49	0
50	142498637
51	0
52	300830572

[0,0,0,1,0,2,0,2,0,7,0,12,0,29,0,55,0,143,0,271,0, 728,0,1428,0,3873,0,7752,0,21318,0,43256,0,120175, 0,246675,0,690678,0,1430715,0,4032015,0,8414610,0, 23841480,0,50067108,0,142498637,0,300830572]