%I A027870
%S A027870 0,0,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,1,0,0,1,1,1,1,0,0,1,0,0,1,1,0,0,0,0,
%T A027870 0,0,0,1,0,1,1,2,3,1,1,1,1,1,0,1,0,2,3,2,2,2,1,1,2,2,3,2,2,2,1,1,0,1,3,
%U A027870 3,1,0,1,1,1,0,0,2,4,2,0,2,3,1,1,0,3,5,3,3,4,2,3,4,1,1,4,5,5,6,6,7,5,5
%N A027870 Number of zeros in 2^n.
%H A027870 Harry J. Smith, <a href="b027870.txt">Table of n, a(n) for n=0,...,1000</
               a>
%e A027870 2^31 = 2147483648 so a(31) = 0 and 2^42 = 4398046511104 so a(42) = 2.
%t A027870 Table[ Count[ IntegerDigits[2^n], 0], {n, 0, 100} ]
%o A027870 (PARI) Count(x, d)= { local(c=0, f); while (x>9, f=x-10*(x\10); if (f==d, 
               c++); x\=10); if (x==d, c++); return(c) } { for (n=0, 1000, a=Count(2^n, 
               0); write("b027870.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), 
               Oct 27 2009]
%Y A027870 Cf. 1's A065712, 2's A065710, 3's A065714, 4's A065715, 5's A065716, 
               6's A065717, 7's A065718, 8's A065719, 9's A065744.
%Y A027870 Sequence in context: A137329 A004579 A081371 this_sequence A070077 A122587 
               A086195
%Y A027870 Adjacent sequences: A027867 A027868 A027869 this_sequence A027871 A027872 
               A027873
%K A027870 nonn,base
%O A027870 0,43
%A A027870 N. J. A. Sloane (njas(AT)research.att.com).
%E A027870 a(99) - a(104) from Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 27 
               2009