91034937domain: NAppears in sequencesa(n) = Sum_{k <= n/2 } binomial(n-2k, 3k).at n=37A137356Number of compositions of 5*n-4 into parts 3 and 5.at n=22A369848a(n) = Sum_{k=0..floor(2*n/3)} binomial(2*k+1,2*n-3*k).at n=27A392454