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A199995 Composite numbers whose multiplicative persistence is 5. 1
679, 688, 697, 796, 868, 886, 976, 1679, 1688, 1769, 1796, 1868, 1886, 1967, 1976, 2379, 2388, 2397, 2468, 2486, 2648, 2684, 2688, 2739, 2793, 2838, 2846, 2864, 2868, 2883, 2886, 2937, 2973, 3279, 3288, 3297, 3367, 3376, 3448, 3484, 3488, 3729, 3736, 3763 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A046505 with respect to A046514.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

679 -> [ 378 ][ 168 ][ 48 ][ 32 ][ 6 ] -> one digit in five steps.

MATHEMATICA

persistence[n_] := Module[{cnt = 0, k = n}, While[k > 9, cnt++; k = Times @@ IntegerDigits[k]]; cnt]; Select[Range[4000], !PrimeQ[#] && persistence[#] == 5 &] (* T. D. Noe, Nov 23 2011 *)

mp5Q[n_]:=CompositeQ[n]&&Length[NestWhileList[ Times@@IntegerDigits[ #]&, n, #>9&]] == 6; Select[Range[4000], mp5Q] (* Harvey P. Dale, Apr 23 2022 *)

CROSSREFS

Cf. A046505 (primes whose multiplicative persistence is 5).

Sequence in context: A097771 A121105 A046514 * A352263 A340091 A164650

Adjacent sequences:  A199992 A199993 A199994 * A199996 A199997 A199998

KEYWORD

nonn,base

AUTHOR

Jaroslav Krizek, Nov 13 2011

STATUS

approved

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Last modified October 7 10:36 EDT 2022. Contains 357270 sequences. (Running on oeis4.)