A184233 Number of strings of numbers x(i=1..n) in 0..2 with sum i^2*x(i)^2 equal to n^2*4.

1, 1, 1, 1, 2, 4, 4, 7, 19, 47, 71, 207, 474, 1077, 2262, 4729, 9770, 18932, 39277, 75259, 142407, 269217, 504234, 930683, 1699058, 3071779, 5553557, 9841969, 17407209, 30656831, 53305283, 92690067, 159391413, 274236367, 467061289, 794526219

Offset: 1

Author

R. H. Hardin Jan 10 2011

Keywords

• nonn

Comments

Column 2 of A184240

Examples

			All solutions for n=5
..0....0
..0....0
..0....2
..0....2
..2....0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..75