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 A213341 #17 Jun 13 2012 17:55:48 %S A213341 0,55,686,6996,79897,799997,8998998,89999998,999989999,9999999999 %N A213341 Smallest palindrome with digital root n and n + 1 decimal digits. %C A213341 Formula a(n) = (44/9*(10^n-1)+(10^n+1)*n) gives for n=0 ... 5 another sequence of palindromic terms a(0) = 0, a(1) = 55, a(2) = 686, a(3) = 7887, a(4) = 88888, a(5) = 988889 (which do not fully comply with the definition "smallest palindrome with digital root n and n+1 decimal digits" - because for n = 3, 4, 5 the terms are not the smallest ones possible). %e A213341 a(1) = 55 because there is no smaller two digit palindrome with a digital root of 1. %Y A213341 Subsequence of A062388. %K A213341 nonn,base,fini,full %O A213341 0,2 %A A213341 _Alexander R. Povolotsky_, Jun 09 2012