129755543domain: NAppears in sequencesa(n) = Sum_{k <= n/2 } binomial(n-2k, 3k+1).at n=37A137357Number of compositions of 5*n-2 into parts 3 and 5.at n=22A369847a(n) = Sum_{k=0..floor((2*n+1)/3)} binomial(2*k+1,2*n-3*k+1).at n=27A391600