Indices of primes in the tribonacci-like sequence, A214899.

Terms

a(0) =0a(1) =2a(2) =3a(3) =9a(4) =13a(5) =27a(6) =35a(7) =39a(8) =87a(9) =95a(10) =97a(11) =99a(12) =113a(13) =131a(14) =233a(15) =971a(16) =3851a(17) =5637a(18) =6553a(19) =106099