OFFSET
1,10
EXAMPLE
a(1) = 1 because there is only one number that can be formed with the digits in 1.
a(10) = 2 because the digits in 10 can be used to make 0, 1, 01, and 10, but only 1 and 10 are both nonzero and unique (obviously, 01=1).
MATHEMATICA
Table[Length[Union[FromDigits/@Flatten[Permutations/@Flatten[ Table[ Partition[ IntegerDigits[t], n, 1], {n, IntegerLength[t]}], 1], 1]/.(0-> Nothing)]], {t, 110}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 21 2016 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Dominick Cancilla, Aug 02 2010
STATUS
approved