A184704 Number of strings of numbers x(i=1..4) in 0..n with sum i*x(i) equal to n*4.

2, 7, 14, 28, 46, 74, 107, 154, 208, 278, 357, 456, 565, 697, 841, 1011, 1195, 1408, 1636, 1897, 2175, 2488, 2820, 3191, 3582, 4015, 4470, 4970, 5494, 6066, 6663, 7312, 7988, 8718, 9477, 10294, 11141, 12049, 12989, 13993, 15031, 16136, 17276, 18487, 19735

Offset: 1

Author

R. H. Hardin, Jan 20 2011

Keywords

• nonn

Comments

Row 4 of A184703.

Examples

			All solutions for n=3:
..0....3....3....1....2....2....2....2....1....1....3....0....0....0
..1....0....3....0....1....3....0....2....2....1....1....2....0....3
..2....3....1....1....0....0....2....2....1....3....1....0....0....2
..1....0....0....2....2....1....1....0....1....0....1....2....3....0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A184703.

Formula

Empirical: a(n) = a(n-1) + a(n-2) - 2*a(n-5) + a(n-8) + a(n-9) - a(n-10).

Empirical g.f.: x*(2 + 5*x + 5*x^2 + 7*x^3 + 4*x^4 + 4*x^5 + x^6 + x^7 + x^8 - x^9) / ((1 - x)^4*(1 + x)^2*(1 + x^2)*(1 + x + x^2)). - Colin Barker, Apr 14 2018