a(n) = prime(n*(n+1)/2+3).

Terms

a(0) =5a(1) =7a(2) =13a(3) =23a(4) =41a(5) =61a(6) =89a(7) =127a(8) =167a(9) =223a(10) =271a(11) =347a(12) =419a(13) =491a(14) =593a(15) =677a(16) =797a(17) =911a(18) =1033a(19) =1171a(20) =1303a(21) =1481a(22) =1619a(23) =1801a(24) =1999a(25) =2203a(26) =2383a(27) =2621a(28) =2803a(29) =3061