478991123domain: NAppears in sequencesTriangle read by rows: T(n, k) is the number of n X n symmetric Toeplitz matrices of rank k using all the integers 0, 1, 2, ..., n-1.at n=77A364790a(n) is the number of n X n nonsingular symmetric Toeplitz matrices using all the integers 0, 1, 2, ..., n-1.at n=11A364791