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%I #23 Jan 14 2016 22:57:11
%S 0,1,1,1,2,2,2,2,1,1,2,2,1,1,1,2,2,1,1,2,2,2,1,1,2,2,2,2,2,3,2,3,3,3,
%T 2,3,3,2,2,3,3,2,3,3,3,3,2,1,1,1,2,2,1,2,2,1,1,2,2,1,1,2,2,3,3,3,3,3,
%U 2,2,3,3,2,3,3,2,2,3,1,1,2,1,2,2,2,1,1,2,1,1,1,2,1,2,2,2,2,2,2,2
%N Number of odd digits in n-th prime.
%C The only zero is the first term. Sequence is unbounded. - _Zak Seidov_, Jan 12 2016
%C From _Robert Israel_, Jan 12 2016: (Start)
%C For any N, the asymptotic density of terms >= N is 1.
%C On the other hand, a(n) = 2 if prime(n) is in A159352, which is conjectured to be infinite.
%C Record values: a(2) = 1, a(5) = 2, a(30) = 3, a(187) = 4, a(1346) = 5, a(10545) = 6, a(86538) = 7, a(733410) = 8.
%C (End)
%H Robert Israel, <a href="/A104638/b104638.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A196564(A000040(n)). - _Michel Marcus_, Oct 05 2013
%p seq(nops(select(type, convert(ithprime(i),base,10),odd)),i=1..100); # _Robert Israel_, Jan 12 2016
%t Table[Count[IntegerDigits[Prime[n]],_?OddQ],{n,100}] (* _Harvey P. Dale_, Jan 22 2012 *)
%t Table[Total[Mod[IntegerDigits[Prime[n]], 2]], {n, 100}] (* _Vincenzo Librandi_, Jan 13 2016 *)
%o (PARI) a(n)=vecsum(digits(prime(n)%2)) \\ _Zak Seidov_, Jan 12 2016
%Y Cf. A104637, A159352.
%K easy,nonn,base
%O 1,5
%A _Zak Seidov_, Mar 18 2005
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