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A046512 Numbers with multiplicative persistence value 3. 3

%I

%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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Last modified November 21 01:23 EST 2019. Contains 329348 sequences. (Running on oeis4.)