337745domain: NAppears in sequencesa(n) = Sum_{k=0..n} C(n-k,4*k).at n=23A005676Number of compositions of 5*n-3 into parts 4 and 5.at n=18A369851a(n) = Sum_{k=0..floor(n/2)} binomial(k,2*(n-2*k)).at n=46A392250