Smallest i such that prime(n) divides gcd(sigma(i), phi(i)) (cf. A009223).

Terms

a(0) =3a(1) =14a(2) =88a(3) =116a(4) =989a(5) =477a(6) =6901a(7) =7067a(8) =6439a(9) =10207a(10) =4976a(11) =10877a(12) =13529a(13) =44461a(14) =79523a(15) =22577a(16) =250277a(17) =62023a(18) =107869a(19) =161027a(20) =75008a(21) =49769a(22) =55277a(23) =183296a(24) =75077a(25) =612463a(26) =381923a(27) =412163a(28) =712423a(29) =153679