%I A105672
%S A105672 1,2,1,8,7,8,1,2,1,26,25,26,19,20,19,26,25,26,1,2,1,8,7,8,1,2,1,80,79,
%T A105672 80,73,74,73,80,79,80,55,56,55,62,61,62,55,56,55,80,79,80,73,74,73,80,
%U A105672 79,80,1,2,1,8,7,8,1,2,1,26,25,26,19,20,19,26,25,26,1,2,1,8,7,8,1,2,1
%N A105672 a(1)=1 then letting f(n)=3^n for f(n)<k<=f(n+1) a(k)=f(n+1)-a(k-f(n)) 
               (b(n,3) using pari code).
%F A105672 a(n+1)=1+sum(k=1, n, (-1)^k*(2-3*3^valuation(k, 3)))
%o A105672 (PARI) b(n,m)=if(n<2,1,m*m^floor(log(n-1)/log(m))-b(n-m^floor(log(n-1)/
               log(m)),m))
%Y A105672 Cf. A105669, A105670, A093347, A093348.
%Y A105672 Sequence in context: A049250 A060587 A081800 this_sequence A005489 A015152 
               A021461
%Y A105672 Adjacent sequences: A105669 A105670 A105671 this_sequence A105673 A105674 
               A105675
%K A105672 nonn
%O A105672 1,2
%A A105672 Benoit Cloitre (benoit7848c(AT)orange.fr), May 03 2005