%I A130823
%S A130823 1,1,1,3,3,3,5,5,5,7,7,7,9,9,9,11,11,11,13,13,13,15,15,15,17,17,17,19,
%T A130823 19,19,21,21,21,23,23,23,25,25,25,27,27,27,29,29,29,31,31,31,33,33,33,
%U A130823 35,35,35,37,37,37,39,39,39,41,41,41,43,43,43,45,45,45,47,47,47,49,49
%N A130823 Each odd number appears thrice.
%C A130823 Partial sums of 1,0,0,2,0,0,2,0,0,2,0,0,... . - Emeric Deutsch (deutsch(AT)duke.poly.edu), 
               Jul 23 2007
%F A130823 G.f.: x(1+x^3)/[(1-x)(1-x^3)]. - Emeric Deutsch (deutsch(AT)duke.poly.edu), 
               Jul 23 2007
%F A130823 Euler transform of length 6 sequence [ 1, 0, 2, 0, 0, -1]. - Michael 
               Somos Aug 16 2007
%F A130823 a(n+3) = a(n)+2. a(1-n) = -a(n). - Michael Somos Aug 16 2007
%F A130823 a(n)=-1+Sum_{k=1..n}{(2/9)*[(k mod 3)+4*((k+1) mod 3)-2*((k+2) mod 3)]}, 
               with n>=1 - Paolo P. Lava (ppl(AT)spl.at), Aug 29 2007, Aug 22 2009
%F A130823 a(n) = floor((n-1)/3)*2+1 - Michael Somos' formula suggested by Johannes 
               Meijer <meijgia@hotmail.com> [From Paolo P. Lava (ppl(AT)spl.at), 
               Aug 21 2009]
%p A130823 G:=x*(1+x^3)/((1-x)*(1-x^3)): Gser:=series(G,x=0,82): seq(coeff(Gser,
               x,n),n= 1..75); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 
               23 2007
%o A130823 (PARI) {a(n) = (n-1)\3*2+1} /* Michael Somos Aug 16 2007 */
%Y A130823 Sequence in context: A130175 A101290 A080605 this_sequence A101435 A077886 
               A096015
%Y A130823 Adjacent sequences: A130820 A130821 A130822 this_sequence A130824 A130825 
               A130826
%K A130823 nonn
%O A130823 1,4
%A A130823 Paul Curtz (bpcrtz(AT)free.fr), Jul 17 2007
%E A130823 More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 23 2007