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A064871
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The minimal number which has multiplicative persistence 7 in base n.
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6
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1409794, 68889, 38200, 17902874277, 1494, 2532, 19526, 15838, 1101, 15820, 943, 2674, 2118, 3275, 412, 3310, 1593, 440, 478, 2036, 456, 713, 738, 633, 658, 705, 907, 643, 803, 641, 653, 797, 484, 991, 814, 877, 1079, 767, 840, 575, 930, 843, 710, 880
(list; graph; refs; listen; history; internal format)
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OFFSET
| 9,1
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COMMENTS
| The persistence of a number is the number of times you need to multiply the digits together before reaching a single digit. a(7)=686285, a(8) seems not to exist.
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LINKS
| M. R. Diamond and D. D. Reidpath, A counterexample to a conjuncture of Sloane and Erdos, J. Recreational Math., 1998 29(2), 89-92. [Broken link?]
Sascha Kurz, Persistence in different bases
C. Rivera, Minimal prime with persistence p
N. J. A. Sloane, The persistence of a number, J. Recreational Math., 6 (1973), 97-98.
Eric Weisstein's World of Mathematics, Multiplicative Persistence
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FORMULA
| a(n) = 8*n-[n/5040] for n > 5039
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EXAMPLE
| a(9)=1409794 because the persistence of 1409794 is 7.
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CROSSREFS
| Cf. A003001, A031346, A064867, A064868, A064869, A064870, A064872.
Sequence in context: A069315 A022209 A203883 * A186837 A054852 A204288
Adjacent sequences: A064868 A064869 A064870 * A064872 A064873 A064874
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KEYWORD
| base,easy,nonn
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AUTHOR
| Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Oct 08 2001
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EXTENSIONS
| Corrected by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 02 2007
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