OFFSET
1,2
COMMENTS
Conjecture: the sequence is defined for all n.
If a(n) = p^n, then for m > n, a(m) >= p^m. In particular, a(n) = 19^n for 13 < n < 86. - David Wasserman, Aug 24 2005
EXAMPLE
a(5) = 3125 = 5^5 with divisors >1: 5, 25, 125, 625, 3125, which are prefix-free in binary: 101, 11001, 1111101, 1001110001, 110000110101.
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Nov 26 2003
EXTENSIONS
More terms from David Wasserman, Aug 24 2005
STATUS
approved