A228185 - OEIS

%I #9 Dec 12 2014 16:07:05

%S 0,14,393,4761,47938,456157,4293575,40357922

%N Number of semiprimes generated from Euler's polynomial x^2 + x + 41 from x = 1 to 10^n.

%e a(4) = 4761 because the number of semiprimes generated from Euler's polynomial x^2 + x + 41 from x = 1 to 10^4 are 4761.

%t a = 0; n = 1; t = {}; Do[If[PrimeOmega[x^2 + x + 41]== 2, a = a + 1]; If[Mod[x, n] == 0, n = n*10; AppendTo[t, a]], {x, 1, 100000000}]; t

%t nn=8;With[{ep=If[PrimeOmega[#]==2,1,0]&/@Table[x^2+x+41,{x,10^nn}]}, Table[ Total[Take[ep,10^n]],{n,nn}]] (* _Harvey P. Dale_, Dec 12 2014 *)

%Y Cf. A228123.

%K nonn,less

%O 1,2

%A _Shyam Sunder Gupta_, Aug 15 2013