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A064871 The minimal number which has multiplicative persistence 7 in base n. 7
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; text; internal format)
OFFSET
9,1
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.
LINKS
M. R. Diamond and D. D. Reidpath, A counterexample to a conjecture of Sloane and Erdos, J. Recreational Math., 1998 29(2), 89-92.
T. Lamont-Smith, Multiplicative Persistence and Absolute Multiplicative Persistence, J. Int. Seq., Vol. 24 (2021), Article 21.6.7.
N. J. A. Sloane, The persistence of a number, J. Recreational Math., 6 (1973), 97-98.
Eric Weisstein's World of Mathematics, Multiplicative Persistence
FORMULA
a(n) = 8*n-[n/5040] for n > 5039.
EXAMPLE
a(9) = 1409794 because the persistence of 1409794 is 7.
CROSSREFS
Sequence in context: A203883 A352611 A337916 * A237397 A301557 A186837
KEYWORD
base,easy,nonn
AUTHOR
Sascha Kurz, Oct 08 2001
EXTENSIONS
Corrected by R. J. Mathar, Nov 02 2007
STATUS
approved

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Last modified June 21 12:50 EDT 2024. Contains 373544 sequences. (Running on oeis4.)