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%I #16 Oct 13 2019 02:31:20
%S 39,47,49,55,57,59,66,68,69,74,75,78,79,86,87,88,89,93,94,95,96,97,98,
%T 139,147,149,155,157,159,166,168,169,174,175,178,179,186,187,188,189,
%U 193,194,195,196,197,198,227,229,236,238,239,246,247,248,249,263,264
%N Numbers with multiplicative persistence value 3.
%H Robert Israel, <a href="/A046512/b046512.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MultiplicativePersistence.html">Multiplicative Persistence</a>
%e 239 -> [ 54 ][ 20 ][ 0 ] -> one digit in three steps.
%p mp:= proc(n) option remember;
%p if n <= 9 then return 0 fi;
%p 1+procname(convert(convert(n,base,10),`*`))
%p end proc:
%p select(mp=3, [$1..1000]); # _Robert Israel_, Feb 12 2019
%t mp3Q[n_]:=Length[NestWhileList[Times@@IntegerDigits[#]&,n,#>9&]]==4; Select[Range[300],mp3Q] (* _Harvey P. Dale_, May 23 2015 *)
%Y Cf. A003001, A014120, A046503.
%K nonn,base
%O 1,1
%A _Patrick De Geest_, Sep 15 1998
%E Offset corrected by _Robert Israel_, Feb 12 2019
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