Least odd prime divisor of 2*prime(n)+1.

Terms

a(0) =5a(1) =7a(2) =11a(3) =3a(4) =23a(5) =3a(6) =5a(7) =3a(8) =47a(9) =59a(10) =3a(11) =3a(12) =83a(13) =3a(14) =5a(15) =107a(16) =7a(17) =3a(18) =3a(19) =11a(20) =3a(21) =3a(22) =167a(23) =179a(24) =3a(25) =7a(26) =3a(27) =5a(28) =3a(29) =227