login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A103131 as a simple table

na(n)
10
21
3-1
4-1
5-1
6-1
7-1
81
9-1
10-1
11-1
121
13-1
14-1
151
161
17-1
18-1
19-1
201
211
22-1
23-1
241
25-1
26-1
27-1
281
29-1
301
31-1
321
331
34-1
351
361
37-1
38-1
391
401
41-1
421
43-1
441
451
46-1
47-1
481
49-1
50-1
511
521
53-1
54-1
551
561
571
58-1
59-1
601
61-1
62-1
631
641
651
661
67-1
681
691
701
71-1
721
73-1
74-1
751
761
771
781
79-1
801
81-1
82-1
83-1
841
851
86-1
871
881
89-1
901
911
921
931
94-1
951
961
97-1
98-1
991
1001
101-1
1021

[0,1,-1,-1,-1,-1,-1,1,-1,-1,-1,1,-1,-1,1,1,-1,-1,
 -1,1,1,-1,-1,1,-1,-1,-1,1,-1,1,-1,1,1,-1,1,1,-1,
 -1,1,1,-1,1,-1,1,1,-1,-1,1,-1,-1,1,1,-1,-1,1,1,1,
 -1,-1,1,-1,-1,1,1,1,1,-1,1,1,1,-1,1,-1,-1,1,1,1,1,
 -1,1,-1,-1,-1,1,1,-1,1,1,-1,1,1,1,1,-1,1,1,-1,-1,
 1,1,-1,1]