Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 21.

A156476

Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 21.

Terms

    a(0) =54a(1) =20a(2) =3552a(3) =11364a(4) =2742240a(5) =56271108a(6) =23882769984a(7) =990946452040

External references