Numbers whose consecutive digits differ by 7.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =7a(8) =8a(9) =9a(10) =18a(11) =29a(12) =70a(13) =81a(14) =92a(15) =181a(16) =292a(17) =707a(18) =818a(19) =929a(20) =1818a(21) =2929a(22) =7070a(23) =8181a(24) =9292a(25) =18181a(26) =29292a(27) =70707a(28) =81818a(29) =92929