Numbers k such that k surrounded by digit '1' is a lucky number.

Terms

a(0) =1a(1) =4a(2) =5a(3) =7a(4) =10a(5) =20a(6) =23a(7) =25a(8) =26a(9) =28a(10) =29a(11) =40a(12) =44a(13) =47a(14) =49a(15) =50a(16) =61a(17) =64a(18) =70a(19) =71a(20) =73a(21) =77a(22) =80a(23) =83a(24) =92a(25) =94a(26) =101a(27) =109a(28) =118a(29) =130