A143595 Triangle read by rows, A000012 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's); 1<=k<=n.
1, 2, 2, 3, 4, 2, 4, 6, 4, 2, 5, 8, 6, 4, 2, 6, 10, 8, 6, 4, 2, 7, 12, 10, 8, 6, 4, 2, 8, 14, 12, 10, 8, 6, 4, 2, 9, 16, 14, 12, 10, 8, 6, 4, 2, 10, 18, 16, 14, 12, 10, 8, 6, 4, 2, 11, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2
Offset: 1
Examples
First few rows of the triangle = 1; 2, 2; 3, 4, 2; 4, 6, 4, 2; 5, 8, 6, 4, 2; 6, 10, 8, 6, 4, 2; 7, 12, 10, 8, 6, 4, 2; ...
Crossrefs
Cf. A056944.
Comments