A201020 Composite numbers whose multiplicative digital root is 6.
6, 16, 28, 32, 44, 48, 68, 74, 82, 84, 86, 116, 123, 128, 132, 144, 147, 148, 161, 168, 174, 182, 184, 186, 213, 218, 224, 228, 231, 238, 242, 244, 246, 264, 267, 272, 276, 282, 288, 289, 298, 312, 321, 328, 344, 368, 374, 377, 378, 382, 386, 387, 414, 417, 418, 422
Offset: 1
Examples
Number 128 is in sequence because 1*2*8=16, 1*6=6.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Crossrefs
Programs
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Mathematica
mdr6Q[n_]:=CompositeQ[n]&&NestWhile[Times@@IntegerDigits[#]&,n,#>9&] ==6; Select[Range[500],mdr6Q] (* Harvey P. Dale, May 30 2015 *)
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