a(n) = pos(M(n)), where M(n) is the n X n matrix with every term = 4, and pos(M(n)) is the positive part of the determinant of M(n); see A380661.

A381724

a(n) = pos(M(n)), where M(n) is the n X n matrix with every term = 4, and pos(M(n)) is the positive part of the determinant of M(n); see A380661.

Terms

    a(0) =4a(1) =16a(2) =192a(3) =3072a(4) =61440a(5) =1474560a(6) =41287680a(7) =1321205760a(8) =47563407360

External references