x such that p = (x^2 + 27*y^2)/4, where p is the n-th prime of the form 3*k+1.

Terms

a(0) =1a(1) =5a(2) =7a(3) =4a(4) =11a(5) =8a(6) =1a(7) =5a(8) =7a(9) =17a(10) =19a(11) =13a(12) =2a(13) =20a(14) =23a(15) =19a(16) =14a(17) =25a(18) =7a(19) =23a(20) =11a(21) =13a(22) =28a(23) =22a(24) =17a(25) =29a(26) =26a(27) =32a(28) =16a(29) =35