a(n) = k-1, where k is smallest number such that A002487(k) = n.

Terms

a(0) =0a(1) =2a(2) =4a(3) =8a(4) =10a(5) =32a(6) =18a(7) =20a(8) =34a(9) =38a(10) =36a(11) =44a(12) =42a(13) =68a(14) =72a(15) =92a(16) =76a(17) =74a(18) =82a(19) =188a(20) =84a(21) =140a(22) =138a(23) =152a(24) =150a(25) =146a(26) =154a(27) =266a(28) =148a(29) =164