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A086690
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Number of primes < 2^prime(n).
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2
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2, 4, 11, 31, 309, 1028, 12251, 43390, 564163, 28192750, 105097565, 5586502348, 80316571436, 305761713237, 4461632979717, 252252704148404, 14458792895301660, 55890484045084135, 3249254387052557215, 48995571600129458363, 190499823401327905601
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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There are 11 primes < 2^5.
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MATHEMATICA
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Table[ PrimePi[ 2^Prime[n]], {n, 1, 14}]
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PROG
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(PARI) primesless2p(n) = \primes less than 2^p { forprime(x=2, n, y=pi(2^x); print1(y", "); ); print(); print(sr) } pi(n) = { c=0; forprime(x=2, n, c++); return(c) }
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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