Numbers of form 2^i*7^j, with i, j >= 0.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =8a(5) =14a(6) =16a(7) =28a(8) =32a(9) =49a(10) =56a(11) =64a(12) =98a(13) =112a(14) =128a(15) =196a(16) =224a(17) =256a(18) =343a(19) =392a(20) =448a(21) =512a(22) =686a(23) =784a(24) =896a(25) =1024a(26) =1372a(27) =1568a(28) =1792a(29) =2048