%I #5 Sep 11 2018 17:04:10
%S 74,37,42,21,26,13,18,9,14,7,12,6,11
%N Repeatedly divide by k, add d: k=2, d=5 case.
%C The next terms are non-integer: 11/2,21/2,21/4,41/4,41/8,81/8,81/16,161/16,... Independently on the initial term, the terms get closer and closer to the limit cycle a(n) = d*k/(k-1), a(n+1) = a(n)/2, a(n+2) = a(n+1)+d = a(n); in this case 10,5,10. Inspired by A112876.
%F From _Chai Wah Wu_, Sep 11 2018: (Start)
%F a(n) = (3*a(n-2) - a(n-4))/2 for n > 4.
%F G.f.: -x*(x + 2)*(69*x^2 - 74)/(x^4 - 3*x^2 + 2). (End)
%Y Cf. A112876.
%K nonn
%O 1,1
%A _Zak Seidov_, Feb 22 2006