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 A064516 Numbers n such that pi(n^2) is prime. 1
 2, 6, 17, 28, 33, 34, 40, 41, 43, 50, 53, 54, 57, 59, 60, 69, 75, 76, 79, 97, 100, 107, 109, 110, 111, 113, 119, 127, 137, 142, 157, 161, 178, 198, 202, 232, 238, 246, 262, 263, 267, 273, 276, 282, 287, 300, 302, 306, 317, 322, 335, 339, 341, 344, 348, 353, 365 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Harry J. Smith, Table of n, a(n) for n = 1..1000 PROG (PARI) pi(x, c=0) = forprime(p=2, x, c++); c for(n=1, 1000, if(isprime(pi(n^2)), print1(n, " "))) (PARI) { n=0; default(primelimit, 3500000000); for (m=1, 10^9, if (isprime(primepi(m^2)), write("b064516.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 17 2009 CROSSREFS Cf. A000720. Sequence in context: A105146 A076660 A024310 * A001441 A204450 A037261 Adjacent sequences:  A064513 A064514 A064515 * A064517 A064518 A064519 KEYWORD easy,nonn AUTHOR Jason Earls, Oct 07 2001 STATUS approved

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Last modified September 22 02:48 EDT 2021. Contains 347605 sequences. (Running on oeis4.)