MathDB

Define a T-grid to be a

3\times3

matrix which satisfies the following two properties: (1) Exactly five of the entries are

1

's, and the remaining four entries are

0

's. (2) Among the eight rows, columns, and long diagonals (the long diagonals are

\{a_{13},a_{22},a_{31}\}

and

\{a_{11},a_{22},a_{33}\}

, no more than one of the eight has all three entries equal. Find the number of distinct T-grids.

Problem Statement