Numbers k such that 1 and 7 occur juxtaposed in the base-10 representation of k but not of k+1.

Terms

a(0) =17a(1) =71a(2) =117a(3) =179a(4) =217a(5) =271a(6) =317a(7) =371a(8) =417a(9) =471a(10) =517a(11) =571a(12) =617a(13) =671a(14) =719a(15) =771a(16) =817a(17) =871a(18) =917a(19) =971a(20) =1017a(21) =1071a(22) =1117a(23) =1179a(24) =1217a(25) =1271a(26) =1317a(27) =1371a(28) =1417a(29) =1471