A127444 Triangle defined as the matrix product A051731*A127442, read by rows.

1, 2, -2, 2, -2, 0, 3, -4, 0, 1, 2, -2, 0, 1, -1, 4, -6, 0, 1, -1, 2, 2, -2, 0, 1, -1, 2, -2, 4, -6, 0, 2, -1, 2, -2, 1, 3, -4, 0, 1, -1, 2, -2, 1, 0, 4, -6, 0, 2, -2, 2, -2, 1, 0, 1, 2, -2, 0, 1, -1, 2, -2, 1, 0, 1, -2, 6, -10, 0, 3, -2, 4, -2, 1

Offset: 1

Author

Gary W. Adamson, Jan 14 2007

Keywords

• tabl
• easy
• sign

Comments

Row sums = 0.

Examples

			First few rows of the triangle are:
1;
2, -2;
2, -2, 0;
3, -4, 0, 1;
2, -2, 0, 1, -1;
4, -6, 0, 1, -1, 2;
2, -2, 0, 1, -1, 2, -2;
...
		

Crossrefs

Cf. A000005 (column k=1), A051731, A127442.

Formula

T(n,k) = sum_{j=k..n} A051731(n,j)*A127442(j,k) = sum_{j=k..n, j|n} A127442(j,k), 1<=k<=n.