Numbers k such that (k^2 + k + 1)/7 is prime.

Terms

a(0) =4a(1) =9a(2) =11a(3) =23a(4) =32a(5) =39a(6) =44a(7) =51a(8) =53a(9) =60a(10) =65a(11) =72a(12) =86a(13) =93a(14) =95a(15) =114a(16) =123a(17) =156a(18) =170a(19) =179a(20) =186a(21) =200a(22) =207a(23) =212a(24) =219a(25) =228a(26) =233a(27) =240a(28) =249a(29) =261