A046512 Numbers with multiplicative persistence value 3.

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

Robert Israel, Table of n, a(n) for n = 1..10000

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

Cf. A003001, A014120, A046503.

Sequence in context: A119028 A252712 A252711 * A143746 A064399 A235151

Adjacent sequences: A046509 A046510 A046511 * A046513 A046514 A046515

Keyword

nonn,base

Author

Patrick De Geest, Sep 15 1998

Extensions

Offset corrected by Robert Israel, Feb 12 2019

Status

approved