A201024 Composite numbers whose multiplicative digital root is 9.

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

Author

Jaroslav Krizek, Nov 25 2011

Keywords

• nonn
• base

Comments

Also composite numbers whose product of digits is 9. Complement of A107695 with respect to A034056.

Examples

			Number 133 is in sequence because 1*3*3=9.
		

Crossrefs

Cf. A107695 (primes whose multiplicative digital root is 9), A034056 (numbers whose multiplicative digital root is 9).

Programs

Mathematica

Select[Range[320000],!PrimeQ[#]&&Times@@IntegerDigits[#]==9&] (* Harvey P. Dale, Aug 27 2012 *)