883404542025domain: NAppears in sequencesG.f.: 16/(7 + 9*sqrt(1 - 32*x)).at n=9A130980Expansion of c(8*x^2)/(1 - x*c(8*x^2)), where c(x) is the g.f. of A000108.at n=18A132375Number of length 2n n-ary words that can be built by repeatedly inserting doublets into the initially empty word.at n=9A294491