a(n) = neg(M(n)), where M(n) is the n X n circulant matrix with (row 1) = (1, 2, ... , n), and neg(M(n)) is the negative part of the determinant of M(n); see A380661.

A383772

a(n) = neg(M(n)), where M(n) is the n X n circulant matrix with (row 1) = (1, 2, ... , n), and neg(M(n)) is the negative part of the determinant of M(n); see A380661.

Terms

    a(0) =0a(1) =-4a(2) =-18a(3) =-610a(4) =-15675a(5) =-772122a(6) =-47282844a(7) =-3918873376a(8) =-410168886615

External references