Indices of prime numbers in A001129.

Terms

a(0) =3a(1) =4a(2) =5a(3) =7a(4) =13a(5) =39a(6) =51a(7) =65a(8) =254a(9) =315a(10) =361a(11) =423a(12) =1109a(13) =1497a(14) =1701a(15) =3711a(16) =3814a(17) =3847a(18) =26779a(19) =47845a(20) =65395a(21) =106481a(22) =106781a(23) =116754