604991601domain: NAppears in sequencesExpansion of (1 - x - x^3)/((1 - x - x^3)^2 - 4*x^4).at n=28A375279a(n) = Sum_{k=0..floor(2*n/3)} binomial(4*n-4*k,2*k).at n=14A375308a(n) = Sum_{k=0..floor(n/2)} binomial(4*k,n-2*k).at n=28A375314