-3040

Appears in sequences

• a(n) = 2*a(n-1) - 6*a(n-2), a(0)=0, a(1)=1.at n=10A088139
• G.f. A(x) satisfies: 4^n/2 = Sum_{k=0..n} [x^k]A(x)^n and also satisfies: ((4+z)^n + z^n)/2 = Sum_{k=0..n} [x^k](A(x)+z*x)^n for all z, where [x^k]A(x)^n denotes the coefficient of x^k in A(x)^n.at n=16A100240
• a(n) = Sum_{k=0..n} C(n,floor(k/2))*(-3)^(n-k).at n=7A127362
• a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(n-1-2*k,n-3*k) * binomial(2*k,k).at n=18A360314