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A201024
Composite numbers whose multiplicative digital root is 9.
0
9, 33, 91, 119, 133, 1119, 1133, 1191, 1313, 1331, 1911, 3113, 3131, 3311, 9111, 11133, 11191, 11313, 11331, 11911, 13113, 13131, 13311, 19111, 31113, 31131, 31311, 33111, 91111, 111133, 111313, 111331, 111911, 113113, 113311, 119111, 131131, 133111, 191111, 311113
OFFSET
1,1
COMMENTS
Also composite numbers whose product of digits is 9. Complement of A107695 with respect to A034056.
EXAMPLE
Number 133 is in sequence because 1*3*3=9.
MATHEMATICA
Select[Range[320000], !PrimeQ[#]&&Times@@IntegerDigits[#]==9&] (* Harvey P. Dale, Aug 27 2012 *)
CROSSREFS
Cf. A107695 (primes whose multiplicative digital root is 9), A034056 (numbers whose multiplicative digital root is 9).
Sequence in context: A020228 A005939 A020326 * A228170 A112888 A048479
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Nov 25 2011
STATUS
approved