a(n) = (prime(n)^2 + 1)/2.

Terms

a(0) =5a(1) =13a(2) =25a(3) =61a(4) =85a(5) =145a(6) =181a(7) =265a(8) =421a(9) =481a(10) =685a(11) =841a(12) =925a(13) =1105a(14) =1405a(15) =1741a(16) =1861a(17) =2245a(18) =2521a(19) =2665a(20) =3121a(21) =3445a(22) =3961a(23) =4705a(24) =5101a(25) =5305a(26) =5725a(27) =5941a(28) =6385a(29) =8065