A178052 - OEIS

%I #10 Mar 27 2013 14:45:34

%S 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 13,14,15,9,10,11,13,14,15,16,10,11,12,13,15,16,17,11,12,13,14,15,17,

%U 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 Digit sums of mountain numbers (cf. A134941).

%C a(n) = A007953(A134941(n));

%C a(n) can be interpreted as the volume of the "mountain" A134941(n);

%C 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 R. Zumkeller, <a href="/A178052/b178052.txt">Table of n, a(n) for n = 1..21846</a> (full sequence)

%e n=552, A134941(552)=134941 (example from A134941):

%e . . level 9: . . . . . . . . X . . . . . .

%e . . level 8: . . . . . . . . X . . . . . .

%e . . level 7: . . . . . . . . X . . . . . .

%e . . level 6: . . . . . . . . X . . . . . .

%e . . level 5: . . . . . . . . X . . . . . .

%e . . level 4: . . . . . . X . X . X . . . .

%e . . level 3: . . . . X . X . X . X . . . .

%e . . level 2: . . . . X . X . X . X . . . .

%e . . level 1: . . X . X . X . X . X . X . .

%e ---------- --------------------------------

%e . . . . a(552) = 1 + 3 + 4 + 9 + 4 + 1 = 22.

%Y Cf. A178053.

%K base,fini,full,nonn

%O 1,2

%A _Reinhard Zumkeller_, May 25 2010