20759040domain: NAppears in sequencesa(n) = 2*(a(n-1) + a(n-2)), a(0) = 0, a(1) = 1.at n=18A002605Expansion of g.f.: x^2*(1 + x - x^2)/(1 - 2*x^2 - 2*x^4).at n=36A160444Elements of A160444, pairs of consecutive entries swapped.at n=37A160572