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Search: id:A096359
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| A096359 |
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Numbers formed by the second nesting of pi(10^n). |
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+0
3
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| 2, 9, 39, 201, 1184, 7702, 53911, 397557, 3048955, 24106415, 195296943, 1613846646, 13556756261, 115465507935, 995112599484
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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Let pi(n) = the number of primes <= n. Then a(n) = pi(pi(n))
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MATHEMATICA
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Table[ Nest[ PrimePi, 10^n, 2], {n, 13}] (from Robert G. Wilson v Jul 01 2004)
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PROGRAM
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(PARI) nestpi(n, m) = { for(x=1, n, z=10^x; for(y=1, m, z=abs(pi(z))); print1(floor(z)", ")) } pi(n) = { local(c, x); c=0; forprime(x=1, n, c++); return(c) \pi(x) prime count function }
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CROSSREFS
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Cf. A006880, A101225, A101226.
Sequence in context: A151016 A151017 A151018 this_sequence A020002 A120700 A075873
Adjacent sequences: A096356 A096357 A096358 this_sequence A096360 A096361 A096362
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Jun 30 2004
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EXTENSIONS
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a(10) - a(15) from Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 01 2004
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