Numbers k such that the squarefree kernel of sigma(k) is equal to the squarefree kernel of 2*k.

Terms

a(0) =6a(1) =28a(2) =120a(3) =135a(4) =270a(5) =496a(6) =672a(7) =891a(8) =1080a(9) =1638a(10) =1782a(11) =3780a(12) =8128a(13) =18600a(14) =20580a(15) =24948a(16) =26208a(17) =30240a(18) =32640a(19) =32760a(20) =35640a(21) =41850a(22) =44226a(23) =55860a(24) =66960a(25) =164640a(26) =167400a(27) =185220a(28) =199584a(29) =200655