a(1) = 1; for n>1, smallest divisor > 1 of 2n-1.
1, 3, 5, 7, 3, 11, 13, 3, 17, 19, 3, 23, 5, 3, 29, 31, 3, 5, 37, 3, 41, 43, 3, 47, 7, 3, 53, 5
1 seqfan posts
Tue Jan 25 10:23:09 CET 2011 [seqfan] Re: OEISWiki : decomposition into weight * level + jump