a(n) = if n is 7-smooth then 1 else 0: characteristic function of 7-smooth numbers.
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0
1 seqfan posts
Wed Feb 16 21:21:33 CET 2011 [seqfan] Re: multiplicative set-like sequences