a(n) is the smallest number x such that gcd(prime(x)+1,x+1) = n.

Terms

a(0) =1a(1) =3a(2) =20a(3) =11a(4) =24a(5) =5a(6) =6a(7) =39a(8) =98a(9) =29a(10) =120a(11) =23a(12) =64a(13) =13a(14) =104a(15) =15a(16) =1716a(17) =323a(18) =284a(19) =499a(20) =62a(21) =1099a(22) =1264a(23) =215a(24) =1274a(25) =51a(26) =512a(27) =447a(28) =1768a(29) =209