22058847domain: NAppears in sequencesa(n) = Sum_{k <= n/2} binomial(n-2k, 3k+2).at n=33A137358Number of compositions of 5*n-2 into parts 3 and 5.at n=20A369847a(n) = Sum_{k=0..floor(2*n/3)} binomial(2*k+1,2*n-3*k).at n=25A392454