

A146170


Percentage (rounded) of odd numbers < 2^n which are primes or squarefree semiprimes.


0



0, 50, 75, 75, 75, 78, 78, 77, 75, 72, 70, 66, 64, 61, 59, 57, 55, 53, 51, 49, 48, 46, 45, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..33.


FORMULA

a(n) = round((A146168(n)+A007053(n)1)/(2^(n1))*100).


EXAMPLE

a(4)=75 because 75% of the 2^3 numbers 1, 3, 5, 7, 9, 11, 13 and 15 are primes or squarefree semiprimes.


CROSSREFS

Cf. A001358(semiprimes), A007053(Number of primes <= 2^n), A146168(Number of odd squarefree semiprimes < 2^n).
Sequence in context: A224552 A039473 A309123 * A217857 A071366 A321517
Adjacent sequences: A146167 A146168 A146169 * A146171 A146172 A146173


KEYWORD

nonn


AUTHOR

Washington Bomfim, Oct 27 2008


STATUS

approved



