Indices of prime tetranacci numbers.

Terms

a(0) =3a(1) =7a(2) =11a(3) =12a(4) =36a(5) =56a(6) =401a(7) =2707a(8) =8417a(9) =14096a(10) =31561a(11) =50696a(12) =53192a(13) =155182