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Numbers with multiplicative digital root value 8.
17

%I #23 Feb 13 2017 20:36:43

%S 8,18,24,29,36,38,42,46,49,63,64,66,67,76,77,79,81,83,88,92,94,97,99,

%T 118,124,129,136,138,142,146,149,163,164,166,167,176,177,179,181,183,

%U 188,192,194,197,199,214,219,222,226,229,233,234,236,237,241,243,248

%N Numbers with multiplicative digital root value 8.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MultiplicativeDigitalRoot.html">Multiplicative Digital Root</a>

%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.

%t dr8Q[n_]:=NestWhile[Times@@IntegerDigits[#]&,n,#>9&]==8; Select[ Range[ 250],dr8Q] (* _Harvey P. Dale_, Jun 10 2011 *)

%Y Cf. A031347.

%Y Cf. A034048, A002275, A034049, A034050, A034051, A034052, A034053, A034054, A034055, A034056 (numbers having multiplicative digital roots 0-9).

%K nonn,base,easy

%O 1,1

%A _Patrick De Geest_, Sep 15 1998