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 A173292 a(n)! has exactly 10^n trailing zeros (a(n) = -1 if no such number exists). 1
 5, 45, 405, 4005, 40010, 400005, 4000005, 40000010, 400000015, 4000000015, 40000000015, 400000000015, 4000000000010, 40000000000015, 400000000000020, -1, -1, -1, 4000000000000000020, 40000000000000000015, -1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS David S. Hart, James E. Marengo, Darren A. Narayan, and David S. Ross, On the number of trailing zeros in n!, College Math. J., 39(2) (2008) p 139-145. A. M. Oller-Marcen, A new look at the trailing zeros of n!, arXiv:0906.4868 [math.NT]. A. M. Oller-Marcen, J. Maria Grau, On the Base-b Expansion of the Number of Trailing Zeros of b^k!, J. Int. Seq. 14 (2011) 11.6.8 CROSSREFS Cf. A173558 (at least 10^n trailing zeros). Sequence in context: A001260 A088505 A067403 * A173558 A022022 A058410 Adjacent sequences:  A173289 A173290 A173291 * A173293 A173294 A173295 KEYWORD base,sign AUTHOR José María Grau Ribas, Feb 15 2010, Feb 22 2010 STATUS approved

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Last modified December 13 08:08 EST 2018. Contains 318082 sequences. (Running on oeis4.)