a(1) = 1, then the smallest number not included earlier and not a string of 1's such that the concatenation a(n), a(n+1) is a palindrome.

A083122

a(1) = 1, then the smallest number not included earlier and not a string of 1's such that the concatenation a(n), a(n+1) is a palindrome.

Terms

    a(0) =1a(1) =21a(2) =2a(3) =12a(4) =121a(5) =1121a(6) =211a(7) =112a(8) =1211a(9) =11121a(10) =2111a(11) =1112a(12) =12111a(13) =111121a(14) =21111a(15) =11112a(16) =121111a(17) =1111121a(18) =211111a(19) =111112a(20) =1211111a(21) =11111121a(22) =2111111a(23) =1111112a(24) =12111111a(25) =111111121a(26) =21111111a(27) =11111112a(28) =121111111a(29) =1111111121

External references