71688

Appears in sequences

• a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A027113.at n=5A027141
• Irreducible polynomial coefficient of singular value associated with sqrt(2n).at n=31A078878
• Number of ways to build a contiguous building with n LEGO blocks of size 1 X 2 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.at n=16A123769
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+103)^2 = y^2.at n=12A157119
• G.f. A(x) satisfies: 1 = ...(((((A(x) - x)^(1/2) - x^2)^(1/2) - x^3)^(1/2) - x^4)^(1/2) - x^5)^(1/2) -...- x^n)^(1/2) -..., an infinite series of nested square roots.at n=15A274965
• Coefficient of x^n in (1 - (n-1)*x - n*x^2)^n.at n=7A307885