A046503 -id:A046503 - cp's OEIS frontend

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

Patrick De Geest, Sep 15 1998

			239 -> [ 54 ][ 20 ][ 0 ] -> one digit in three steps.

Robert Israel, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Multiplicative Persistence

Cf. A003001, A014120, A046503.

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

mp3Q[n_]:=Length[NestWhileList[Times@@IntegerDigits[#]&,n,#>9&]]==4; Select[Range[300],mp3Q] (* Harvey P. Dale, May 23 2015 *)

Offset corrected by Robert Israel, Feb 12 2019

A199993 Composite numbers whose multiplicative persistence is 3.

Original entry on oeis.org

39, 49, 55, 57, 66, 68, 69, 74, 75, 78, 86, 87, 88, 93, 94, 95, 96, 98, 147, 155, 159, 166, 168, 169, 174, 175, 178, 186, 187, 188, 189, 194, 195, 196, 198, 236, 238, 246, 247, 248, 249, 264, 266, 267, 272, 274, 276, 279, 284, 288, 289, 292, 294, 297, 298, 299

Offset: 1

Jaroslav Krizek, Nov 13 2011

Complement of A046503 with respect to A046512.

			147 -> 1 * 4 * 7 -> [ 28 ] -> 2 * 8 -> [ 16 ] -> 1 * 6 -> [ 6 ] -> one digit in three steps.

Harvey P. Dale, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Multiplicative Persistence

Cf. A046503 (primes whose multiplicative persistence is 3).

Select[Range[300],CompositeQ[#]&&Length[NestWhileList[Times@@ IntegerDigits[ #]&,#,#>9&]] == 4&] (* Harvey P. Dale, Mar 29 2023 *)

{ A046512 } minus { A046503 }.

cp's OEIS Frontend

A046512 Numbers with multiplicative persistence value 3.

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