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A287534
Composite numbers whose digits are restricted to 1, 3, 7, and 9.
0
9, 33, 39, 77, 91, 93, 99, 111, 113, 117, 119, 133, 171, 177, 319, 333, 339, 371, 377, 391, 393, 399, 711, 713, 717, 731, 737, 771, 777, 779, 791, 793, 799, 913, 917, 931, 933, 939, 973, 979, 993, 999
OFFSET
1,1
MATHEMATICA
Select[Flatten@ Array[FromDigits /@ Tuples[{1, 3, 7, 9}, #] &, 3], CompositeQ] (* Michael De Vlieger, Jun 01 2017 *)
CROSSREFS
Sequence in context: A208136 A130444 A177697 * A145849 A111045 A020226
KEYWORD
nonn,base
AUTHOR
Luke Zieroth, May 26 2017
STATUS
approved