%I #13 Feb 08 2013 18:13:38

%S 0,0,1,2,3,4,5,6,8,9,10,11,13,15,16,18,20,22,24,25,29,30,32,34,36,39,

%T 42,44,46,48,52,54,58,61,62,66,68,72,75,78,81,85,89,92,96,99,101,105,

%U 109,114,118,122,126,129,133,137,141,146,150,154,158,162,167,172,177,181,187,191,195,200

%N Number of primes <= n-th quarter-square.

%F a(n) = A000720(A002620(n)), n >= 1.

%t Table[PrimePi[n^2/4], {n, 75}] (* _Alonso del Arte_, Feb 05 2013 *)

%Y Partial sums of A220492. A bisection is A038107, n >= 1.

%Y Cf. A000040, A000720, A002620, A014085, A111208.

%K nonn

%O 1,4

%A _Omar E. Pol_, Feb 05 2013