Primes of the form (5+ a triangular number A000217).

Terms

a(0) =5a(1) =11a(2) =41a(3) =71a(4) =83a(5) =281a(6) =383a(7) =1181a(8) =1601a(9) =2351a(10) =2633a(11) =3491a(12) =3833a(13) =4283a(14) =5783a(15) =6221a(16) =6791a(17) =8783a(18) =10301a(19) =10883a(20) =11633a(21) =12251a(22) =14033a(23) =15581a(24) =18341a(25) =26111a(26) =26801a(27) =30881a(28) =31883a(29) =34721