A200253 Number of 0..n arrays x(0..3) of 4 elements with each no smaller than the sum of its previous elements modulo (n+1).

8, 24, 69, 135, 267, 448, 750, 1125, 1690, 2376, 3339, 4459, 5957, 7680, 9900, 12393, 15516, 19000, 23265, 27951, 33583, 39744, 47034, 54925, 64142, 74088, 85575, 97875, 111945, 126976, 144024, 162129, 182512, 204120, 228285, 253783, 282131, 312000

Offset: 1

Author

R. H. Hardin, Nov 15 2011

Keywords

• nonn

Comments

Row 4 of A200251.

Examples

			Some solutions for n=6:
..4....4....0....1....2....0....1....4....0....1....3....2....1....3....2....2
..4....6....2....1....6....1....6....5....0....3....5....2....1....6....6....6
..6....5....5....6....1....2....0....6....2....5....1....5....6....3....2....4
..1....6....3....6....2....4....3....3....5....5....3....4....5....6....3....6
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A200251.

Formula

Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + 3*a(n-4) - 4*a(n-5) + 4*a(n-7) - 3*a(n-8) + 2*a(n-9) - 2*a(n-11) + a(n-12).

Empirical g.f.: x*(8 + 8*x + 21*x^2 + 13*x^3 + 21*x^4 + 12*x^5 + 13*x^6 - 2*x^7 + 3*x^8 - 2*x^10 + x^11) / ((1 - x)^5*(1 + x)^3*(1 + x^2)^2). - Colin Barker, Feb 23 2018