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A086680
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Number of primes < 4^n.
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0
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0, 2, 6, 18, 54, 172, 564, 1900, 6542, 23000, 82025, 295947, 1077871, 3957809, 14630843, 54400028, 203280221, 762939111, 2874398515, 10866266172, 41203088796, 156661034233, 597116381732, 2280998753949, 8731188863470
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| These numbers approximate the sum of primes < 2^n. The sum of primes < 2^20 =
A130739(20) = 41162256126. The number of primes < 2^40 = 41203088796. The
error is -0.000991993. From A007053, we have number of
primes < 2^74 =375744164937699609596 and sum of
primes < 2^37 =375743480734175191581 for an error of -0.0000018209325.
Justification sumprimes(n) ~ Pi(n^2) can br found in the link.
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LINKS
| Cino Hilliard, Sum of primes less than n [Cino Hilliard, Feb 13 2009]
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EXAMPLE
| for n=2, 2,3,5,7,11,13 are the 6 primes < 2^4.
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CROSSREFS
| Cf. A007053, A130739.
Sequence in context: A192338 A114464 A062415 * A148455 A094590 A004529
Adjacent sequences: A086677 A086678 A086679 * A086681 A086682 A086683
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KEYWORD
| nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), Jul 28 2003
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EXTENSIONS
| Extended by Cino Hilliard (hillcino368(AT)hotmail.com), Feb 13 2009
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