Monotonic ordering of nonnegative differences 3^i-7^j, for 40>= i>=0, j>=0.

Terms

a(0) =0a(1) =2a(2) =8a(3) =20a(4) =26a(5) =32a(6) =74a(7) =80a(8) =194a(9) =236a(10) =242a(11) =386a(12) =680a(13) =722a(14) =728a(15) =1844a(16) =2138a(17) =2180a(18) =2186a(19) =2876a(20) =4160a(21) =6218a(22) =6512a(23) =6554a(24) =6560a(25) =17282a(26) =19340a(27) =19634a(28) =19676a(29) =19682