423644570442domain: NAppears in sequencesBending a piece of wire of length n+1 (configurations that can only be brought into coincidence by turning the figure over are counted as different).at n=25A001444a(n) = 3^n*(3^(n+1)+1)/2.at n=12A051407a(n) = n! * Sum_{i+2j+3k=n} 1/(i!*(2j)!*(3k)!).at n=26A094717