a(n) is the smallest prime divisor of (A177929(n)-1)*(A177929(n)+1).

Terms

a(0) =3a(1) =5a(2) =3a(3) =11a(4) =3a(5) =5a(6) =3a(7) =29a(8) =3a(9) =59a(10) =3a(11) =7a(12) =5a(13) =3a(14) =7a(15) =137a(16) =3a(17) =5a(18) =3a(19) =281a(20) =3a(21) =5a(22) =3a(23) =569a(24) =3a(25) =7a(26) =5a(27) =3a(28) =1151a(29) =3