a(n) is the smallest x such that the quotient d(x)/d(x+1) equals n, where d = A000005.

Terms

a(0) =2a(1) =6a(2) =12a(3) =30a(4) =112a(5) =60a(6) =192a(7) =210a(8) =180a(9) =240a(10) =13312a(11) =420a(12) =12288a(13) =2112a(14) =1008a(15) =1320a(16) =2162688a(17) =1800a(18) =786432a(19) =2160a(20) =4800a(21) =15360a(22) =62914560a(23) =2520a(24) =6480a(25) =61440a(26) =6300a(27) =8640a(28) =3489660928a(29) =12240