Numbers k in A018900 with arithmetic derivative k' (A003415) in A018900.

Terms

a(0) =6a(1) =9a(2) =20a(3) =40a(4) =65a(5) =68a(6) =96a(7) =144a(8) =192a(9) =528a(10) =576a(11) =1028a(12) =4097a(13) =73728a(14) =81920a(15) =262148a(16) =557056a(17) =6291456a(18) =9437184a(19) =12582912a(20) =201326592a(21) =335544320a(22) =2415919104