OFFSET
1,10
COMMENTS
For all numbers using only prime digits a(n) = 0. For a 'k' digit number using 1 and/or only composite digits a(n) = (10^k-1)/9.
EXAMPLE
a(4206) = 1011
a(10235479) = 11000101.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Sep 09 2003
EXTENSIONS
More terms from David Wasserman, May 25 2005
STATUS
approved