Numbers k such that Sum_{i=1..k} phi(i)/gcd(k,i) is an integer.

Terms

a(0) =1a(1) =4a(2) =9a(3) =16a(4) =27a(5) =36a(6) =63a(7) =64a(8) =108a(9) =112a(10) =121a(11) =132a(12) =192a(13) =256a(14) =375a(15) =432a(16) =464a(17) =625a(18) =768a(19) =961a(20) =1024a(21) =1296a(22) =1309a(23) =1600a(24) =1620a(25) =2205a(26) =2304a(27) =2525a(28) =2597a(29) =3072