0,1

a(n) = Determinant( A-A^2+ A^3- A^4+ A^5-... 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.

"Le sequenze di numeri interi", G. Balzarotti, P.P. Lava, 2008, ed. Hoepli.

a(1)=Determinant(A)=7!=5040

seq(Determinant(sum(A^i*(-1)^(i-1), i=1..n)), n=1..20);

A111490, A158040, A158041, A158042, A158043, A158044, A158045, A158046, A158047, A158048, A158049

Sequence in context: A135456 A055362 A053876 this_sequence A063411 A008552 A010800

Adjacent sequences: A158047 A158048 A158049 this_sequence A158051 A158052 A158053

sign

Giorgio Balzarotti & Paolo P. Lava (greenblue(AT)tiscali.it), Mar 11 2009