OFFSET
0,1
COMMENTS
a(n) = Determinant(A - A^2 + A^3 - A^4 + A^5 - ... - (-1)^n*A^n)
where A is the submatrix A(1..8,1..8) of the matrix with factorial determinant
A= [[1,1,1,1,1,1,...], [1,2,1,2,1,2,...], [1,2,3,1,2,3,...], [1,2,3,4,1,2,...], [1,2,3,4,5,1,...], [1,2,3,4,5,6,...], ...]; note: Determinant A(1..n,1..n) = (n-1)!.
a(n) is even with respect to signs of power of A.
REFERENCES
G. Balzarotti and P. P. Lava, Le sequenze di numeri interi, Hoepli, 2008
EXAMPLE
a(1) = Determinant(A) = 7! = 5040.
MAPLE
seq(Determinant(sum(A^i*(-1)^(i-1), i=1..n)), n=1..20);
CROSSREFS
KEYWORD
sign
AUTHOR
Giorgio Balzarotti & Paolo P. Lava, Mar 11 2009
STATUS
approved