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 A303572 #16 Apr 29 2018 12:20:01 %S A303572 101,10001,10101,121,212,1221,12021,20102,10201,12021,232,313,1331, %T A303572 13031,30103,10301,13031,343,414,1441,14041,40104,14041,14241,2442, %U A303572 12421,12321,2332,13231,13431,3443,13431,13531,535,515,1551,15051,50105,15051,15251,2552,12521 %N A303572 a(n) = palindrome arising when A228410(n+1) is formed (if there is more than one, use the smallest). %C A303572 Let A228410(n) = X, A228410(n+1) = Y. The digits of X and Y can be rearranged to form a palindrome, possibly in several ways; a(n) is the smallest such palindrome. %C A303572 Numbers with an even number of digits without a digit 0 are in A113585. - _David A. Corneth_, Apr 28 2018 %H A303572 David A. Corneth, <a href="/A303572/b303572.txt">Table of n, a(n) for n = 0..999</a> %Y A303572 Cf. A113585, A228410. %K A303572 nonn,base %O A303572 0,1 %A A303572 _N. J. A. Sloane_, Apr 27 2018 %E A303572 More terms by _David A. Corneth_, Apr 27 2018