A186071 - OEIS

A186071 as a simple table

n	a(n)
1	31
2	331
3	3331
4	33331
5	333331
6	3333331
7	33333331
8	0
9	0
10	0
11	0
12	0
13	37
14	337
15	0
16	0
17	0
18	311
19	0
20	313
21	3313
22	0
23	0
24	0
25	317
26	0
27	0
28	0
29	0
30	0
31	0
32	0
33	0
34	0
35	0
36	0
37	0
38	0
39	331
40	3331
41	33331
42	333331
43	3333331
44	33333331
45	0
46	0
47	0
48	0
49	0
50	337
51	0
52	0
53	0
54	0
55	0
56	0
57	0
58	0
59	0
60	347
61	3347
62	33347
63	0
64	349
65	0
66	0
67	0
68	353

[31,331,3331,33331,333331,3333331,33333331,0,0,0, 0,0,37,337,0,0,0,311,0,313,3313,0,0,0,317,0,0,0,0, 0,0,0,0,0,0,0,0,0,331,3331,33331,333331,3333331, 33333331,0,0,0,0,0,337,0,0,0,0,0,0,0,0,0,347,3347, 33347,0,349,0,0,0,353]