102733

Appears in sequences

• a(n)=number of tilings of a 4 X n rectangle using tiles that are either 1 X 1 squares or trominoes (here by a tromino we mean a 2 X 2 square with the upper right 1 X 1 square removed; no rotations allowed).at n=11A105262
• Number of (n+1)X(n+1) -8..8 symmetric matrices with every 2X2 subblock having sum zero and one or three distinct values.at n=10A211468