1888140

Appears in sequences

• Half the number of n X n binary matrices, symmetric about the diagonal and under 90-degree rotation, having equal row sums.at n=15A140879
• Half the number of symmetric n X n binary matrices having equal row sums.at n=7A140988
• Number of nonnegative integer arrays of length n+3 with new values 0 upwards introduced in order, and containing the value n-1.at n=19A211563