Numbers of form 4^i*7^j, with i, j >= 0.

Terms

a(0) =1a(1) =4a(2) =7a(3) =16a(4) =28a(5) =49a(6) =64a(7) =112a(8) =196a(9) =256a(10) =343a(11) =448a(12) =784a(13) =1024a(14) =1372a(15) =1792a(16) =2401a(17) =3136a(18) =4096a(19) =5488a(20) =7168a(21) =9604a(22) =12544a(23) =16384a(24) =16807a(25) =21952a(26) =28672a(27) =38416a(28) =50176a(29) =65536