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 A243824 #47 Oct 29 2021 06:06:34 %S A243824 2,1,4,1,6,3,8,1,10,5,11,5,12,3,14,7,16,1,18,9,22,5 %N A243824 Two-column array A(n,s) of pairs (n,s) read by row where s is the smallest seed number such that the Reverse and Add! trajectory of s contains n (excluding cases where n=s). %H A243824 Felix Fröhlich, <a href="/A243824/a243824_1.txt">C++ program for this sequence</a> %e A243824 A(10,1)=16 is in the array because 16 is the 9th number appearing in the Reverse and Add! trajectory of a smaller number. %e A243824 A(10,2)=1 is in the array because 1 + 1 = 2, 2 + 2 = 4, 4 + 4 = 8, 8 + 8 = 16, so 1 is the smallest seed number whose Reverse and Add! trajectory contains 16. %e A243824 Array begins: %e A243824 2 1 %e A243824 4 1 %e A243824 6 3 %e A243824 8 1 %e A243824 10 5 %e A243824 11 5 %e A243824 12 3 %e A243824 14 7 %e A243824 16 1 %e A243824 18 9 %e A243824 22 5 %Y A243824 Cf. A006960, A023109, A033665, A063048, A070788, A077594. %K A243824 nonn,base,tabf,more %O A243824 2,1 %A A243824 _Felix Fröhlich_, Jun 11 2014