A199984 Composite numbers whose multiplicative digital root is 4.

4, 14, 22, 27, 39, 72, 93, 98, 114, 122, 141, 172, 189, 198, 212, 217, 221, 249, 266, 294, 319, 333, 338, 346, 364, 391, 411, 429, 436, 492, 626, 634, 662, 712, 721, 767, 772, 776, 793, 819, 833, 891, 913, 918, 924, 931, 942, 973, 981, 1114, 1122, 1127, 1139

Offset: 1

Author

Jaroslav Krizek, Nov 13 2011

Keywords

• nonn
• base

Comments

Complement of A199983 with respect to A034051.

Examples

			Number 172 is in sequence because 1*7*2=14, 1*4=4.
		

Crossrefs

Cf. A199983 (primes whose multiplicative digital root is 4).

Cf. A034051 (numbers whose multiplicative digital root is 4).

Programs

Mathematica

cn4Q[n_]:=NestWhile[Times@@IntegerDigits[#]&,n,#>9&]==4; Select[Select[ Range[ 1200],CompositeQ],cn4Q] (* Harvey P. Dale, Apr 28 2018 *)