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A199994 Composite numbers whose multiplicative persistence is 4. 0
77, 177, 268, 286, 348, 355, 377, 378, 384, 387, 438, 446, 464, 476, 477, 483, 489, 498, 535, 553, 575, 628, 644, 668, 674, 678, 682, 686, 687, 699, 717, 737, 738, 746, 747, 755, 764, 767, 768, 771, 772, 774, 776, 777, 778, 783, 786, 788, 793, 826, 834, 837 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Complement of A046504 with respect to A046513.
LINKS
EXAMPLE
77 -> [ 49 ][ 36 ][ 18 ][ 8 ] -> one digit in four steps.
MATHEMATICA
persistence[n_] := Module[{cnt = 0, k = n}, While[k > 9, cnt++; k = Times @@ IntegerDigits[k]]; cnt]; Select[Range[1000], ! PrimeQ[#] && persistence[#] == 4 &]
CROSSREFS
Cf. A046504 (primes whose multiplicative persistence is 4).
Sequence in context: A075253 A217790 A046513 * A043518 A044409 A044790
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Nov 13 2011
STATUS
approved

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Last modified May 26 00:57 EDT 2024. Contains 372806 sequences. (Running on oeis4.)