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%I #30 Aug 19 2021 09:43:57
%S 0,0,1,1,2,3,4,5,6,8,11,14,18,24,31,42,54,72,97,128,172,229,309,418,
%T 564,760,1028,1393,1900,2585,3512,4792,6542,8952,12251,16777,23000,
%U 31579,43390,59631,82025,112957,155611,214516,295947,408493,564163,779638
%N Number of squared primes <= 2^n.
%H Ray Chandler, <a href="/A060967/b060967.txt">Table of n, a(n) for n = 0..125</a> (terms 0-63 from Harry J. Smith, terms 64-112 from Hiroaki Yamanouchi)
%e n=8, squared primes not exceeding 256 are 4, 9, 25, 49, 121, 169 so a(8)=6.
%t Table[ PrimePi[ Floor[ 2^(g/2)//N ] ], {g, 1, 75} ]
%o (PARI) { f="b060967.txt"; default(primelimit, 4294965247); a=n=-1; s=1; forprime (p=2, 4294965247, a++; if (p^2>s, write(f, n++, " ", a); s*=2); if (p^2>s, write(f, n++, " ", a); s*=2); ) } \\ _Harry J. Smith_, Jul 15 2009
%Y Cf. A007053, A036386.
%K nonn
%O 0,5
%A _Labos Elemer_, May 09 2001
%E a(0) prepended by _Harry J. Smith_, Jul 15 2009
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