Numbers k such that sigma(k^2) and Sum_{d|k} d*sigma(d) are both multiples of k.

Terms

a(0) =1a(1) =39a(2) =793a(3) =2379a(4) =7137a(5) =76921a(6) =230763a(7) =692289a(8) =2076867a(9) =8329831a(10) =24989493a(11) =53695813a(12) =74968479a(13) =161087439a(14) =224905437a(15) =243762649a(16) =324863409a(17) =375870691a(18) =483262317a(19) =731287947a(20) =1127612073a(21) =1449786951a(22) =2094136707a(23) =2193863841a(24) =2631094837a(25) =3382836219a(26) =3606816823