Numbers k such that nonprime(k) divides k^2.

Terms

a(0) =1a(1) =2a(2) =4a(3) =18a(4) =72a(5) =130a(6) =280a(7) =495a(8) =840a(9) =900a(10) =930a(11) =1216a(12) =1880a(13) =2646a(14) =3182a(15) =3762a(16) =17437a(17) =21600a(18) =29400a(19) =30654a(20) =35207a(21) =45024a(22) =58230a(23) =266133a(24) =1051980a(25) =1204164a(26) =1204320a(27) =2193408a(28) =2494520a(29) =2549745