A228185 Number of semiprimes generated from Euler's polynomial x^2 + x + 41 from x = 1 to 10^n.

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

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Example

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.

Mathematica

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
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 *)

Crossrefs

Cf. A228123.

Sequence in context: A211421 A097310 A223003 * A041367 A041364 A353609

Adjacent sequences: A228182 A228183 A228184 * A228186 A228187 A228188

Keyword

nonn,less

Author

Shyam Sunder Gupta, Aug 15 2013

Status

approved