-17345

Appears in sequences

• a(n) = (n-2)*a(n-2) - a(n-3), with a(0)=0, a(1)=1, a(2)=2.at n=15A122048
• Triangle T(n,k), read by rows, defined by T(n,k)=3*T(n-1,k)-T(n-1,k-1)-T(n-2,k), T(0,0)=1, T(1,0)=2, T(1,1)=-1, T(n,k)=0 if k<0 or if k>n.at n=46A123971