%I A053824
%S A053824 0,1,2,3,4,1,2,3,4,5,2,3,4,5,6,3,4,5,6,7,4,5,6,7,8,1,2,3,4,5,2,3,4,5,6,
%T A053824 3,4,5,6,7,4,5,6,7,8,5,6,7,8,9,2,3,4,5,6,3,4,5,6,7,4,5,6,7,8,5,6,7,8,9,
%U A053824 6,7,8,9,10,3,4,5,6,7,4,5,6,7,8,5,6,7,8,9,6,7,8,9,10,7,8,9,10,11,4,5,6
%N A053824 Sum of digits of n written in base 5.
%C A053824 Also the fixed point of the morphism 0->{0,1,2,3,4}, 1->{1,2,3,4,5}, 
               2->{2,3,4,5,6}, etc. - Robert G. Wilson v Jul 27 2006.
%C A053824 a(n) = A138530(n,5) for n > 4. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               Mar 26 2008
%H A053824 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               DigitSum.html">Digit Sum</a>
%F A053824 a(0)=0, a(5n+i)=a(n)+i 0<=i<=4; a(n)=n-4*(sum(k>0, floor(n/5^k))=n-4*A027868(n). 
               - Benoit Cloitre, Dec 19, 2002
%e A053824 a(20)=4+0=4 because 20 is written as 40 base 5
%t A053824 Table[Plus @@ IntegerDigits[n, 5], {n, 0, 100}] (* or *)
%t A053824 Nest[Flatten[ #1 /. a_Integer -> Table[a + i, {i, 0, 4}]] &, {0}, 4] 
               (* Robert G. Wilson v Jul 27 2006 *)
%o A053824 (PARI) a(n)=if(n<1,0,if(n%5,a(n-1)+1,a(n/5)))
%Y A053824 Cf. A000120, A007953.
%Y A053824 Sequence in context: A092196 A100878 A145172 this_sequence A033925 A064866 
               A024855
%Y A053824 Adjacent sequences: A053821 A053822 A053823 this_sequence A053825 A053826 
               A053827
%K A053824 base,nonn
%O A053824 0,3
%A A053824 Henry Bottomley (se16(AT)btinternet.com), Mar 28 2000