A048516 Array T read by diagonals: T(m,n)=number of subsets S of {1,2,3,...,m+n-1} such that |S|>1 and |a-b|>=m for all distinct a and b in S, m=1,2,3,...; n=1,2,3,...

0, 0, 1, 0, 4, 1, 0, 11, 3, 1, 0, 26, 7, 3, 1, 0, 57, 14, 6, 3, 1, 0, 120, 26, 11, 6, 3, 1, 0, 247, 46, 19, 10, 6, 3, 1, 0, 502, 79, 31, 16, 10, 6, 3, 1, 0, 1013, 133, 49, 25, 15, 10, 6, 3, 1, 0, 2036, 221, 76, 38, 22, 15, 10, 6, 3, 1, 0, 4083, 364

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• tabl

Examples

			Diagonals: {0}; {1,0}; {4,1,0}; ...
		

Links

• Sean A. Irvine, Java program (github)

Crossrefs

A000295 (row 1), A001924 (row 2), A050228 (row 3).

Formula

T(m,n) = [x^m] 1/((1-x^2)*(1-x-x^n)). - Sean A. Irvine, Jun 19 2021