|
Search: id:A146169
|
|
|
| A146169 |
|
Percentage (rounded) of semiprimes <= 2^n which are odd and square-free. |
|
+0
1
|
|
| 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; listen)
|
|
|
OFFSET
|
2,3
|
|
|
COMMENT
|
More than 84% of the semiprimes in the interval [4, 2^32] are odd and square-free. This percentage appears to rise indefinitely as n grows.
|
|
FORMULA
|
a(n) = round(A146168(n)/A125527(n)*100)
|
|
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 square-free.
|
|
CROSSREFS
|
Cf. A001358(semiprimes), A125527(Number of semiprimes <= 2^n), A146168(Number of odd square-free semiprimes < 2^n).
Sequence in context: A034069 A116037 A081643 this_sequence A045020 A069961 A140146
Adjacent sequences: A146166 A146167 A146168 this_sequence A146170 A146171 A146172
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
W. Bomfim (webonfim(AT)bol.com.br), Oct 27 2008
|
|
|
Search completed in 0.002 seconds
|
