k th digit of a(n) is the number of different digits within 3 of k (not including k).

Terms

a(0) =11a(1) =111a(2) =122a(3) =212a(4) =221a(5) =1111a(6) =1222a(7) =2122a(8) =2212a(9) =2221a(10) =11111a(11) =12221a(12) =21222a(13) =22122a(14) =22212a(15) =111111a(16) =122212a(17) =122221a(18) =133322a(19) =212221a(20) =221222a(21) =222122a(22) =223331a(23) =1111111a(24) =1222122a(25) =1222212a(26) =1222221a(27) =1333222a(28) =2122212a(29) =2122221