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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
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
Sequence in context: A323827 A275850 A112505 * A270648 A331034 A057155
KEYWORD
easy,nonn,base
AUTHOR
Zak Seidov, Mar 18 2005
STATUS
approved

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Last modified March 19 03:33 EDT 2024. Contains 370952 sequences. (Running on oeis4.)