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A086693
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Number of primes less than prime(n)^prime(n).
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0
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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 9 primes less than 3^3 = 27, namely 2,3,5,7,11,13,17,19,23. Since 3 is prime(2), a(2) = 9.
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MATHEMATICA
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f[n_] := Block[{p = Prime@ n}, PrimePi[p^p]]; Array[f, 5] (* Michael De Vlieger, Mar 17 2015 *)
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PROG
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(PARI) primeslesspp(n) = /* primes less than p^p */ { forprime(x=2, n, y=primepi(x^x); print1(y", "); ); }
(Magma) [ #PrimesUpTo(NthPrime(n)^NthPrime(n)): n in [1..4] ]; // Vincenzo Librandi, Mar 17 2015
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CROSSREFS
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KEYWORD
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hard,more,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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