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A199991 Nonprime numbers whose multiplicative persistence is 1. 0
10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 30, 32, 33, 40, 42, 50, 51, 60, 70, 80, 81, 90, 91, 100, 102, 104, 105, 106, 108, 110, 111, 112, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 130, 132, 133, 140, 141, 142, 150, 160, 161, 170, 171, 180, 190 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A046501 with respect to A046510.

LINKS

Table of n, a(n) for n=1..56.

EXAMPLE

105 -> 1 * 0 * 5 = 0; one digit in one step.

MATHEMATICA

persistence[n_] := Module[{cnt = 0, k = n}, While[k > 9, cnt++; k = Times @@ IntegerDigits[k]]; cnt]; Select[Range[200], ! PrimeQ[#] && persistence[#] == 1 &] (* T. D. Noe, Nov 23 2011 *)

CROSSREFS

Cf. A046501 (primes whose multiplicative persistence is 1).

Sequence in context: A230597 A330904 A124867 * A161598 A122426 A141322

Adjacent sequences:  A199988 A199989 A199990 * A199992 A199993 A199994

KEYWORD

nonn,base

AUTHOR

Jaroslav Krizek, Nov 13 2011

STATUS

approved

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Last modified September 24 23:43 EDT 2022. Contains 356951 sequences. (Running on oeis4.)