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 A303571 #17 Dec 30 2018 04:04:24 %S A303571 101,111,101,10001,10201,212,202,10201,12021,232,313,1331,13031,30103, %T A303571 10301,13031,343,414,1441,14041,40104,14041,14241,2442,12421,12121, %U A303571 12021,102201,102201,102201,1002001,1005001,15051,515,525,2552,15251,15351,3553,13531 %N A303571 a(n) = palindrome arising when A228407(n+1) is formed (if there is more than one, use the smallest). %C A303571 Let A228407(n) = X, A228407(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. %H A303571 Rémy Sigrist, <a href="/A303571/b303571.txt">Table of n, a(n) for n = 0..29999</a> %H A303571 Rémy Sigrist, <a href="/A303571/a303571.gp.txt">PARI program for A303571</a> %o A303571 (PARI) See Links section. %Y A303571 Cf. A228407. %K A303571 nonn,base %O A303571 0,1 %A A303571 _N. J. A. Sloane_, Apr 27 2018 %E A303571 More terms from _Rémy Sigrist_, Dec 27 2018