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A064517 Numbers k such that pi(k) is a square. 2
1, 2, 7, 8, 9, 10, 23, 24, 25, 26, 27, 28, 53, 54, 55, 56, 57, 58, 97, 98, 99, 100, 151, 152, 153, 154, 155, 156, 227, 228, 311, 312, 419, 420, 541, 542, 543, 544, 545, 546, 661, 662, 663, 664, 665, 666, 667, 668, 669, 670, 671, 672, 827, 828, 1009, 1010, 1011 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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, 2000, if(issquare(pi(n)), print1(n, " ")))

(PARI) { n=0; for (m=1, 10^9, if (issquare(primepi(m)), write("b064517.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 17 2009

CROSSREFS

Cf. A000720.

Sequence in context: A152769 A283565 A047527 * A270804 A167457 A287515

Adjacent sequences:  A064514 A064515 A064516 * A064518 A064519 A064520

KEYWORD

easy,nonn

AUTHOR

Jason Earls, Oct 07 2001

STATUS

approved

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Last modified September 20 06:19 EDT 2019. Contains 327212 sequences. (Running on oeis4.)