Indices k such that A019322(k) = Phi[k](4) is prime, where Phi is a cyclotomic polynomial.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =8a(5) =12a(6) =16a(7) =20a(8) =28a(9) =40a(10) =60a(11) =92a(12) =96a(13) =104a(14) =140a(15) =148a(16) =156a(17) =300a(18) =356a(19) =408a(20) =596a(21) =612a(22) =692a(23) =732a(24) =756a(25) =800a(26) =952a(27) =996a(28) =1004a(29) =1228