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 A104638 Number of odd digits in n-th prime. 4
 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, 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, 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS The only zero is the first term. Sequence is unbounded. - Zak Seidov, Jan 12 2016 From Robert Israel, Jan 12 2016: (Start) For any N, the asymptotic density of terms >= N is 1. On the other hand, a(n) = 2 if prime(n) is in A159352, which is conjectured to be infinite. 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. (End) LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A196564(A000040(n)). - Michel Marcus, Oct 05 2013 MAPLE seq(nops(select(type, convert(ithprime(i), base, 10), odd)), i=1..100); # Robert Israel, Jan 12 2016 MATHEMATICA Table[Count[IntegerDigits[Prime[n]], _?OddQ], {n, 100}] (* Harvey P. Dale, Jan 22 2012 *) Table[Total[Mod[IntegerDigits[Prime[n]], 2]], {n, 100}] (* Vincenzo Librandi, Jan 13 2016 *) PROG (PARI) a(n)=vecsum(digits(prime(n)%2)) \\ Zak Seidov, Jan 12 2016 CROSSREFS Cf. A104637, A159352. Sequence in context: A323827 A275850 A112505 * A270648 A057155 A037812 Adjacent sequences:  A104635 A104636 A104637 * A104639 A104640 A104641 KEYWORD easy,nonn,base AUTHOR Zak Seidov, Mar 18 2005 STATUS approved

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Last modified June 20 09:27 EDT 2019. Contains 324234 sequences. (Running on oeis4.)