a(n) is the smallest k such that (n+1)*phi(k) = (n-1)*psi(k).

Terms

a(0) =2a(1) =3a(2) =95a(3) =5a(4) =143a(5) =7a(6) =319a(7) =323a(8) =559a(9) =11a(10) =117317a(11) =13a(12) =1007a(13) =899a(14) =1919a(15) =17a(16) =201983a(17) =19a(18) =441283a(19) =1763a(20) =394697a(21) =23a(22) =4031a(23) =5249a(24) =2911a(25) =3239a(26) =23519a(27) =29a(28) =3599a(29) =31