Numbers k such that 4 and 6 occur juxtaposed in the base-10 representation of k but not of k-1.

Terms

a(0) =46a(1) =64a(2) =146a(3) =164a(4) =246a(5) =264a(6) =346a(7) =364a(8) =446a(9) =460a(10) =546a(11) =564a(12) =640a(13) =664a(14) =746a(15) =764a(16) =846a(17) =864a(18) =946a(19) =964a(20) =1046a(21) =1064a(22) =1146a(23) =1164a(24) =1246a(25) =1264a(26) =1346a(27) =1364a(28) =1446a(29) =1460