login
A228185
Number of semiprimes generated from Euler's polynomial x^2 + x + 41 from x = 1 to 10^n.
0
0, 14, 393, 4761, 47938, 456157, 4293575, 40357922
OFFSET
1,2
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
KEYWORD
nonn,less
AUTHOR
Shyam Sunder Gupta, Aug 15 2013
STATUS
approved