241813226151domain: NAppears in sequencesCentral trinomial coefficients: largest coefficient of (1 + x + x^2)^n.at n=26A002426Sum of the squares of the trinomial coefficients (A027907).at n=13A082758a(n) = Sum_{k=0..n} C(n,k)*((-1)^n*(C(k,n-k)-C(k,n-k-1))+C(n-k,k+1)).at n=26A273020