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

1,1

Comments

Complement of A201019 with respect to A034053.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

Number 128 is in sequence because 1*2*8=16, 1*6=6.

Mathematica

mdr6Q[n_]:=CompositeQ[n]&&NestWhile[Times@@IntegerDigits[#]&, n, #>9&] ==6; Select[Range[500], mdr6Q] (* Harvey P. Dale, May 30 2015 *)

Crossrefs

Cf. A201019 (primes whose multiplicative digital root is 6), A034053 (numbers whose multiplicative digital root is 6).

Sequence in context: A265389 A320693 A274848 * A088818 A346620 A032422

Adjacent sequences: A201017 A201018 A201019 * A201021 A201022 A201023

Keyword

nonn,base

Author

Jaroslav Krizek, Nov 25 2011

Status

approved