Numbers k such that 3 and 9 occur juxtaposed in the base-10 representation of k but not of k+1.

Terms

a(0) =39a(1) =93a(2) =139a(3) =193a(4) =239a(5) =293a(6) =339a(7) =399a(8) =439a(9) =493a(10) =539a(11) =593a(12) =639a(13) =693a(14) =739a(15) =793a(16) =839a(17) =893a(18) =939a(19) =993a(20) =1039a(21) =1093a(22) =1139a(23) =1193a(24) =1239a(25) =1293a(26) =1339a(27) =1399a(28) =1439a(29) =1493