-21523361

Appears in sequences

• An inverse Catalan transform of A003462.at n=31A106233
• a(1)=-1; a(2)=-1; a(3)=-2; a(n) = 4*a(n-1) - 3*a(n-2) for n >= 4.at n=17A123183
• a(n)=4a(n-1)-7a(n-2)+6a(n-3)-3a(n-4), n>4.at n=34A140343
• a(n) = (-1)^(n+1) * (3^n+1)/2.at n=16A341463