OFFSET
1,2
FORMULA
a(n+1) = 1 + Sum_{k=1..n} (-1)^k*(2-3*3^valuation(k, 3)).
MAPLE
A105672 := proc(n)
option remember;
if n = 1 then
1;
else
fn1 := A064235(n) ;
fn := fn1/3 ;
fn1-procname(n-fn) ;
end if;
end proc:
seq(A105672(n), n=1..80) ; # R. J. Mathar, Nov 06 2011
MATHEMATICA
A064235[n_] := 3^Ceiling[Log[3, n]]; a[1] = 1; a[n_] := a[n] = A064235[n] - a[n - A064235[n]/3]; Table[a[n], {n, 1, 81}] (* Jean-François Alcover, Jul 09 2013, after R. J. Mathar *)
PROG
(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))
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, May 03 2005
STATUS
approved