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Search: id:A064869
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| A064869 |
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The minimal number which has multiplicative persistence 5 in base n. |
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+0
16
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| 244140624, 3629, 1601, 1535, 394, 679, 317, 1099, 127, 135, 582, 187, 168, 157, 201, 159, 230, 215, 180, 185, 246, 181, 188, 195, 198, 323, 239, 255, 259, 267, 239, 287, 295, 293, 310, 313, 280, 377, 375, 395, 347, 360, 321, 370, 439, 431, 458, 355, 362
(list; graph; listen)
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OFFSET
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5,1
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COMMENT
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The persistence of a number is the number of times you need to multiply the digits together before reaching a single digit. a(3) and a(4) seem not to exist.
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LINKS
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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
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a(n) = 6*n-[n/120] for n > 119
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EXAMPLE
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a(9)=394 because 394=[477]->[237]->[46]->[26]->[13]->[3] and no smaller n has persistence 5 in base 9.
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CROSSREFS
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Cf. A003001, A031346, A064867, A064868, A064870, A064871, A064872.
Sequence in context: A046327 A158936 A029831 this_sequence A016824 A016860 A016980
Adjacent sequences: A064866 A064867 A064868 this_sequence A064870 A064871 A064872
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KEYWORD
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base,easy,nonn
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AUTHOR
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Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Oct 09 2001
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