OFFSET
1,2
COMMENTS
Supersequence of A284294.
EXAMPLE
1111 is in the sequence because 1*1*1*1 = 1 = 9^0.
MATHEMATICA
FromDigits /@ Select[Join @@ Map[Tuples[{1, 3, 9}, #] &, Range@ 4], IntegerQ@ Log[9, Times @@ #] &] (* Michael De Vlieger, Mar 25 2017 *)
PROG
(Magma) Set(Sort([n: n in [1..10000], k in [0..20] | &*Intseq(n) eq 9^k]))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Mar 25 2017
STATUS
approved