A139872 - OEIS

%I #18 Sep 08 2022 08:45:34

%S 11,59,71,179,191,251,311,419,599,719,839,911,971,1259,1439,1499,1511,

%T 1571,1871,2039,2099,2399,2531,2579,2699,2711,2819,3191,3359,3371,

%U 3491,3719,3851,4019,4079,4139,4211,4271,4679,4691,4799,4871,4931

%N Primes of the form 11x^2 + 15y^2.

%C Discriminant = -660. See A139827 for more information.

%H Vincenzo Librandi and Ray Chandler, <a href="/A139872/b139872.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi]

%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)

%F The primes are congruent to {11, 59, 71, 119, 179, 191, 251, 311, 419, 551, 599} (mod 660).

%t QuadPrimes2[11, 0, 15, 10000] (* see A106856 *)

%o (Magma) [ p: p in PrimesUpTo(6000) | p mod 660 in {11, 59, 71, 119, 179, 191, 251, 311, 419, 551, 599}]; // _Vincenzo Librandi_, Jul 30 2012

%o (PARI) list(lim)=my(v=List(),w,t); for(x=1, sqrtint(lim\11), w=11*x^2; for(y=0, sqrtint((lim-w)\15), if(isprime(t=w+15*y^2), listput(v,t)))); Set(v) \\ _Charles R Greathouse IV_, Mar 07 2017

%K nonn,easy

%O 1,1

%A _T. D. Noe_, May 02 2008