49825

Appears in sequences

• Number of 2 X 2 matrices having all terms in {1,...,n} and even determinant.at n=16A211064
• Free polyominoes with 2n squares, having 180-degree rotational symmetry about a square mid-side, but no reflective symmetry.at n=9A234008
• a(n) = 3*2^n + 3*4^n + 6^(n+1) + 1.at n=5A290396