Positive y such that p = (x^2 + 27*y^2)/4 where p is the n-th prime of the form 6*k+1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =1a(5) =2a(6) =3a(7) =3a(8) =3a(9) =1a(10) =1a(11) =3a(12) =4a(13) =2a(14) =1a(15) =3a(16) =4a(17) =1a(18) =5a(19) =3a(20) =5a(21) =5a(22) =2a(23) =4a(24) =5a(25) =3a(26) =4a(27) =2a(28) =6a(29) =1