421724160

Appears in sequences

• 8-fold convolution of A000302 (powers of 4).at n=8A054338
• a(n) = (0^n + 4^n * binomial(2*n,n))/2.at n=8A098402
• T(n,k)=Number of pairs of orthogonal (-x,y) vectors of length k*(x+y), where x/y is the n-th rational <= 1, ordered first by y and then x, e.g. 1/1, 1/2, 1/3, 2/3, 1/4, 3/4 ...at n=28A225987
• a(n) = max{A380114(n, k) : k = 0..n}.at n=16A380115