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 A196563 Number of even digits in decimal representation of n. 47
 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 1, 2, 1, 2, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,21 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 FORMULA a(n) = A055642(n) - A196564(n); a(A014261(n)) = 0; a(A007928(n)) > 0. From Hieronymus Fischer, May 30 2012: (Start) a(n) = sum_{j=0..m} (1 + floor(n/(2*10^j)) - floor(n/(2*10^j) + (1/2)),  where m=floor(log_10(n)). a(10n+k) = a(n) + a(k), 0<=k<10, n>=0. a(n) = a(floor(n/10))+a(n mod 10), n>=0. a(n) = sum_{j=0..m} a(floor(n/10^j) mod 10), n>=0. a(A014263(n)) = 1 + floor(log_5(n-1)), n>1. G.f.: g(x) = 1 + (1/(1-x))*sum_{j>=0} x^(2*10^j)/(1+ x^10^j). (End) MAPLE A196563 := proc(n)         if n =0 then                 1;         else                 convert(n, base, 10) ;                 add(1-(d mod 2), d=%) ;         end if: end proc: # R. J. Mathar, Jul 13 2012 MATHEMATICA Table[Count[Mod[IntegerDigits[n], 2], 0][n], {n, 0, 100}] (* Zak Seidov, Oct 13 2015 *) Table[Count[IntegerDigits[n], _?EvenQ], {n, 0, 120}] (* Harvey P. Dale, Feb 22 2020 *) PROG (Haskell) a196563 n = length [d | d <- show n, d `elem` "02468"] -- Reinhard Zumkeller, Feb 22 2012, Oct 04 2011 (PARI) a(n) = #select(x->(!(x%2)), if (n, digits(n), [0])); \\ Michel Marcus, Oct 14 2015 (Python) def a(n): return sum(1 for d in str(n) if d in "02468") print([a(n) for n in range(100)]) # Michael S. Branicky, May 15 2022 CROSSREFS Cf. A014261, A014263, A027868, A046034, A055640, A055641, A055642, A061217, A102669-A102685, A122640, A196564. Sequence in context: A326398 A140195 A196564 * A198890 A305831 A022927 Adjacent sequences:  A196560 A196561 A196562 * A196564 A196565 A196566 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Oct 04 2011 STATUS approved

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Last modified July 4 02:09 EDT 2022. Contains 355063 sequences. (Running on oeis4.)