OFFSET
1,1
COMMENTS
All terms > 3 are composite.
FORMULA
a(n) = 3 * A032917(n).
MATHEMATICA
Table[FromDigits/@Tuples[{3, 9}, n], {n, 5}]//Flatten (* Harvey P. Dale, Sep 20 2022 *)
PROG
(Magma) [n: n in [1..100000] | Set(IntegerToSequence(n, 10)) subset {3, 9}]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Apr 06 2017
STATUS
approved