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 A108768 Primes that appear in the sequence p:=x^2+x+1, sieved with a quadratic sieve construction. 0
 3, 7, 13, 7, 31, 43, 19, 73, 13, 37, 19, 157, 61, 211, 241, 307, 127, 421, 463, 79, 601, 31, 37, 757, 271, 67, 331, 151, 1123, 397, 97, 43, 67, 1483, 223, 547, 1723, 139, 631, 283, 109, 103, 61, 181, 2551, 379, 919, 409, 2971, 79, 103, 3307, 163, 3541, 523, 97, 3907 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence appears in a website available on web.archive (see Quadratic Sieve Construction link). There is a single appearance of the first term 3, while all other primes appear twice. See A256148 for a version of the sequence consistent with the current version of the website where each prime appears only once. - Ray Chandler, Jul 05 2015 LINKS Bernhard Helmes, Prime sieving on the polynomial f(n)=n^2+n+1. Bernhard Helmes, Quadratic Sieve Construction (web.archive). PROG (MuPAD) // from Quadratic Sieve Construction link. liste_max:=10000; for x from 1 to liste_max do     liste_x[x]:=x^2+x+1;     liste_prim[x]:=1; end_for; x:=1; while (x1) then      print ("Prim ", p, "x = ", x, isprime (p)) ;      // Aussiebung      while (stelle

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Last modified April 9 07:30 EDT 2020. Contains 333344 sequences. (Running on oeis4.)