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A046512
Numbers with multiplicative persistence value 3.
5
39, 47, 49, 55, 57, 59, 66, 68, 69, 74, 75, 78, 79, 86, 87, 88, 89, 93, 94, 95, 96, 97, 98, 139, 147, 149, 155, 157, 159, 166, 168, 169, 174, 175, 178, 179, 186, 187, 188, 189, 193, 194, 195, 196, 197, 198, 227, 229, 236, 238, 239, 246, 247, 248, 249, 263, 264
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Multiplicative Persistence
EXAMPLE
239 -> [ 54 ][ 20 ][ 0 ] -> one digit in three steps.
MAPLE
mp:= proc(n) option remember;
if n <= 9 then return 0 fi;
1+procname(convert(convert(n, base, 10), `*`))
end proc:
select(mp=3, [$1..1000]); # Robert Israel, Feb 12 2019
MATHEMATICA
mp3Q[n_]:=Length[NestWhileList[Times@@IntegerDigits[#]&, n, #>9&]]==4; Select[Range[300], mp3Q] (* Harvey P. Dale, May 23 2015 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Sep 15 1998
EXTENSIONS
Offset corrected by Robert Israel, Feb 12 2019
STATUS
approved