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 A015994 #20 Sep 15 2022 04:07:56 %S A015994 1,5,59,69,166,79,188,193,1397,829,167,2069,1797,849,177,999,739,1798, %T A015994 989,6999,1297,869,187,89,10797,10853,10921,10971,13297,10548,13293, %U A015994 17793,20889,700269,106977,108933,80359,13697,10794,15891,1009227,1007619,1009246 %N A015994 Smallest k such that the smallest palindrome > k in the Reverse and Add! trajectory of k is reached after exactly n iterations. %C A015994 Variant of A023109 allowing k to be palindromic itself. %C A015994 Smallest k such that A033665(k) = n. %H A015994 Fabien Gelineau, <a href="/A015994/b015994.txt">Table of n, a(n) for n = 1..82</a> %o A015994 (PARI) iterationstosmallestpalindrome(n, bound) = my(x=n, i=0, d); while(1, if(i > bound, return(-1)); x=x+eval(concat(Vecrev(Str(x)))); i++; d=digits(x); if(d==Vecrev(d), return(i))) %o A015994 a(n) = for(k=1, oo, if(iterationstosmallestpalindrome(k, n)==n, return(k))) \\ _Felix Fröhlich_, May 28 2022 %Y A015994 Cf. A023109. %K A015994 nonn,base %O A015994 1,2 %A A015994 _Felix Fröhlich_, May 28 2022; original entry _N. J. A. Sloane_, Dec 11 1999 %E A015994 Keyword "dead" removed, more terms added and entry revised by _Felix Fröhlich_, May 28 2022; Jun 22 2022