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A146169
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Percentage (rounded) of semiprimes <= 2^n which are odd and squarefree.
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0
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0, 0, 17, 20, 36, 48, 56, 61, 65, 69, 71, 73, 75, 76, 77, 78, 79, 80, 80, 81, 81, 82, 82, 82, 83, 83, 83, 83, 84, 84, 84, 84
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,3
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COMMENTS
| More than 84% of the semiprimes in the interval [4, 2^32] are odd and squarefree. This percentage appears to rise indefinitely as n grows.
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FORMULA
| a(n) = round(A146168(n)/A125527(n)*100)
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EXAMPLE
| a(5)= 20 since the interval [4, 2^5] contains 10 semiprimes, namely 4,6,9,10,14,15,21,22,25 and 26; and two of those semiprimes, (15 and 21), are odd and squarefree.
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CROSSREFS
| Cf. A001358(semiprimes), A125527(Number of semiprimes <= 2^n), A146168(Number of odd squarefree semiprimes < 2^n).
Sequence in context: A034069 A116037 A081643 * A045020 A069961 A140146
Adjacent sequences: A146166 A146167 A146168 * A146170 A146171 A146172
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KEYWORD
| nonn
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AUTHOR
| W. Bomfim (webonfim(AT)bol.com.br), Oct 27 2008
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