%I A072560
%S A072560 3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,1,1,3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,1,
%T A072560 1,3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,1,1,3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,
%U A072560 1,1,3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,1,1,3,9,3,3,1,3,3,9,3,3,1,3,3,9,3
%N A072560 Denominators of w(n) where w(1)=w(2)=w(3)=1, w(n)=(w(n-1)*w(n-2)+(w(n-1)+w(n-2))/
               3) / w(n-3).
%C A072560 Sequence contains 1,3 or 9 only and is periodic with period (3,9,3,3,
               1,3,3,9,3,3,1,3,3,9,3,1,1,1) of length 18.
%F A072560 a(n)=1/1377*{-122*(n mod 18)+31*[(n+1) mod 18]+31*[(n+2) mod 18]+184*[(n+3) 
               mod 18]+490*[(n+4) mod 18]-428*[(n+5) mod 18]+31*[(n+6) mod 18]-122*[(n+7) 
               mod 18]+184*[(n+8) mod 18]+31*[(n+9) mod 18]+490*[(n+10) mod 18]-428*[(n+11) 
               mod 18]+31*[(n+12) mod 18]-122*[(n+13) mod 18]+184*[(n+14) mod 18]+31*[(n+15) 
               mod 18]+490*[(n+16) mod 18]-428*[(n+17) mod 18]} with n>=0 - Paolo 
               P. Lava (ppl(AT)spl.at), Nov 29 2006
%Y A072560 Cf. A072561, A072557.
%Y A072560 Sequence in context: A098323 A016674 A091670 this_sequence A074959 A010632 
               A021258
%Y A072560 Adjacent sequences: A072557 A072558 A072559 this_sequence A072561 A072562 
               A072563
%K A072560 nonn
%O A072560 1,1
%A A072560 Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 06 2002