OFFSET
1,2
COMMENTS
Contribution from Hagen von Eitzen, Aug 16 2009: (Start)
a(n) = a(A007947(n)). As a consequence one may focus on squarefree n.
Let p be a prime. Then a(p)=p; a(2p) = 2p if p is Mersenne, otherwise a(2p) = p; a(3p) in {p, 2p+1}. (End)
EXAMPLE
35 is factored as 5*7. The binary representations of 5 and 7 are 101 and 111. The smallest positive integer that contains both these binary representations as substrings is 23 (decimal) = 10111 in binary. So a(35) = 23.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Leroy Quet, Jul 01 2009
EXTENSIONS
More terms from Hagen von Eitzen, Aug 16 2009
STATUS
approved