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 A179987 #3 Mar 30 2012 18:51:06 %S A179987 1,2,3,4,5,6,7,8,9,8,7,6,5,4,3,2,1,2,3,4,5,6,7,8,9,10,9,10,11,10,9,8, %T A179987 7,6,5,4,3,4,5,6,7,8,9,10,11,12,11,12,13,12,11,10,9,8,7,6,5,6,7,8,9, %U A179987 10,11,12,13,14,13,14,15,14,13,12,11,10,9,8,7,8,9,10,11,12,13,14,15,16,15,16 %N A179987 Digital sums of A108971. %C A179987 a(n) = A007953(A108971(n)); %C A179987 ABS(a(n+1) - a(n)) = 1 by definition of A108971; %C A179987 a(A179988(n)) = n and a(m) <> n for m < A179988(n). %H A179987 R. Zumkeller, <a href="/A179987/b179987.txt">Table of n, a(n) for n = 1..10000</a> %K A179987 base,nonn %O A179987 1,2 %A A179987 _Reinhard Zumkeller_, Aug 09 2010