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 A122840 a(n) is the number of 0's at the end of n when n is written in base 10. 40
 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,100 COMMENTS Greatest k such that 10^k divides n. a(n) = the number of digits in n - A160093(n). a(A005117(n)) <= 1. - Reinhard Zumkeller, Mar 30 2010 See A054899 for the partial sums. - Hieronymus Fischer, Jun 08 2012 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 S. Ikeda and K. Matsuoka, On transcendental numbers generated by certain integer sequences, Siauliai Math. Semin., 8 (16) 2013, 63-69. FORMULA a(n) = A160094(n) - 1. From Hieronymus Fischer, Jun 08 2012: (Start) With m = floor(log_10(n)), frac(x) = x-floor(x): a(n) = Sum_{j=1..m} (1 - ceiling(frac(n/10^j))). a(n) = m + Sum_{j=1..m} (floor(-frac(n/10^j))). a(n) = A054899(n) - A054899(n-1). G.f.: g(x) = Sum_{j>0} x^10^j/(1-x^10^j). (End) EXAMPLE a(160) = 1 because there is 1 zero at the end of 160 when 160 is written in base 10. PROG (Haskell) a122840 n = if n < 10 then 0 ^ n else 0 ^ d * (a122840 n' + 1)             where (n', d) = divMod n 10 -- Reinhard Zumkeller, Mar 09 2013 (PARI) a(n)=valuation(n, 10) \\ Charles R Greathouse IV, Feb 26 2014 (Python) def a(n): return len(str(n)) - len(str(int(str(n)[::-1]))) # Indranil Ghosh, Jun 09 2017 CROSSREFS A007814 is the base 2 equivalent of this sequence. Cf. A160094, A160093, A001511, A070940, A122841, A027868, A054899, A122840, A196563, A196564, A004151. Sequence in context: A118553 A102448 A102683 * A083919 A063665 A276306 Adjacent sequences:  A122837 A122838 A122839 * A122841 A122842 A122843 KEYWORD nonn,base,easy AUTHOR Reinhard Zumkeller, Sep 13 2006 STATUS approved

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Last modified December 5 17:16 EST 2020. Contains 338954 sequences. (Running on oeis4.)