Average of squares of divisors is an integer: numbers k such that sigma_0(k) divides sigma_2(k).

Terms

a(0) =1a(1) =3a(2) =4a(3) =5a(4) =7a(5) =11a(6) =12a(7) =13a(8) =15a(9) =17a(10) =19a(11) =20a(12) =21a(13) =23a(14) =25a(15) =27a(16) =28a(17) =29a(18) =31a(19) =33a(20) =35a(21) =37a(22) =39a(23) =41a(24) =43a(25) =44a(26) =47a(27) =48a(28) =49a(29) =51