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Integer part of the area of circles with prime radii.
0

%I #21 Jan 06 2024 21:28:54

%S 12,28,78,153,380,530,907,1134,1661,2642,3019,4300,5281,5808,6939,

%T 8824,10935,11689,14102,15836,16741,19606,21642,24884,29559,32047,

%U 33329,35968,37325,40114,50670,53912,58964,60698,69746,71631,77437,83468,87615,94024,100659

%N Integer part of the area of circles with prime radii.

%F a(n) = floor(Pi*prime(n)^2). - _Michel Marcus_, Mar 11 2015

%e a(2) = floor(Pi*prime(2)^2) = floor(Pi*9) = 28.

%t Table[Floor[Pi*Prime[n]^2], {n, 60}] (* _Wesley Ivan Hurt_, Jan 06 2024 *)

%o (PARI) f(n) = forprime(x=1,n,print1(floor(Pi*x^2)","))

%o (Magma) [Floor(Pi(RealField(2*n))*NthPrime(n)^2): n in [1..80]]; // _Vincenzo Librandi_, Mar 11 2015

%Y Cf. A000040.

%K nonn

%O 1,1

%A _Cino Hilliard_, Aug 22 2004

%E More terms from _Wesley Ivan Hurt_, Jan 06 2024