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 A178052 #10 Mar 27 2013 14:45:34 %S A178052 1,4,5,6,7,8,9,10,11,7,8,9,10,11,12,13,7,9,10,11,12,13,14,8,9,11,12, %T A178052 13,14,15,9,10,11,13,14,15,16,10,11,12,13,15,16,17,11,12,13,14,15,17, %U A178052 18,12,13,14,15,16,17,19,13,14,15,16,17,18,19,9,11,12,13,14,15,16,10,11,13,14 %N A178052 Digit sums of mountain numbers (cf. A134941). %C A178052 a(n) = A007953(A134941(n)); %C A178052 a(n) can be interpreted as the volume of the "mountain" A134941(n); %C A178052 a(21846) = A007953(12345678987654321) = A000217(9)+A000217(8) = 45+36 = 81 is the largest term, as A134941(21846)=12345678987654321 is the most voluminous "mountain". %H A178052 R. Zumkeller, <a href="/A178052/b178052.txt">Table of n, a(n) for n = 1..21846</a> (full sequence) %e A178052 n=552, A134941(552)=134941 (example from A134941): %e A178052 . . level 9: . . . . . . . . X . . . . . . %e A178052 . . level 8: . . . . . . . . X . . . . . . %e A178052 . . level 7: . . . . . . . . X . . . . . . %e A178052 . . level 6: . . . . . . . . X . . . . . . %e A178052 . . level 5: . . . . . . . . X . . . . . . %e A178052 . . level 4: . . . . . . X . X . X . . . . %e A178052 . . level 3: . . . . X . X . X . X . . . . %e A178052 . . level 2: . . . . X . X . X . X . . . . %e A178052 . . level 1: . . X . X . X . X . X . X . . %e A178052 ---------- -------------------------------- %e A178052 . . . . a(552) = 1 + 3 + 4 + 9 + 4 + 1 = 22. %Y A178052 Cf. A178053. %K A178052 base,fini,full,nonn %O A178052 1,2 %A A178052 _Reinhard Zumkeller_, May 25 2010