This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A083985 #11 Sep 29 2024 21:10:34 %S A083985 3,1,1,3,1,1,9,1,3,1,6,1,2,9,2,1,1,1,1,1,9,1,1,3,1,6,1,9,2,1,12,1,3,1, %T A083985 1,9,1,3,1,1,1,2,9,2,1,1,2,3,1,9,1,1,3,1,3,1,9,2,1,12,1,2,3,1,1,1,3,1, %U A083985 1,3,1,1,1,1,3,1,1,3,1,1,1,1,1,1,3,3,1,1,7,1,3,3,1,1,1,1,1,1,1,1,2,3,2,1,6 %N A083985 If k is a number with exactly two distinct decimal digits, say a and b, neither of which is 0 (i.e., a member of A101594), define the self-complement of k, SC(k), to be the number obtained by replacing a with b and vice versa. Then a(n) = gcd(A101594(n), SC(A101594(n))). %e A083985 12 is the term corresponding to k = 48 as (48,84) = 1 %e A083985 a(7) = gcd(18, 81) = 9. %Y A083985 Cf. A083983, A083984, A083986. %Y A083985 Cf. A101594. %K A083985 base,nonn %O A083985 1,1 %A A083985 _Amarnath Murthy_, May 22 2003 %E A083985 Corrected and extended by _David Wasserman_, Dec 07 2004 %E A083985 Offset corrected by _Andrew Howroyd_, Sep 29 2024