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 A377191 #21 Nov 11 2024 08:59:21 %S A377191 0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0, %T A377191 1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1, %U A377191 1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,0 %N A377191 Smallest number of digits that must be changed in n to obtain a palindrome (without changing the first digit to 0). %C A377191 The sequence is unbounded, with a(n) = k first occurring at n = A377192(k). %F A377191 a(A002113(n)) = 0, a(A029742(n)) > 0. %F A377191 a(n) = 0 iff A136522(n) = 1, a(n) > 0 iff A136522(n) = 0. %e A377191 a(12) = 1 because 12 is not a palindrome, but changing 1 digit appropriately (either the first or second in this case) yields a palindrome. %Y A377191 Cf. A002113, A029742, A136522, A377192. %K A377191 nonn,base,easy %O A377191 0,1011 %A A377191 _Franz Vrabec_, Oct 19 2024