A267235 Number of length-6 0..n arrays with no following elements greater than or equal to the first repeated value.

8, 223, 1790, 8274, 27854, 76237, 180292, 382404, 745548, 1359083, 2345266, 3866486, 6133218, 9412697, 14038312, 20419720, 29053680, 40535607, 55571846, 74992666, 99765974, 131011749, 170017196, 218252620, 277388020, 349310403

Offset: 1

Author

R. H. Hardin, Jan 12 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 6 of A267232.

Formula

Empirical: a(n) = n^6 + (197/60)*n^5 + 3*n^4 + (3/4)*n^3 - (1/30)*n.

Conjectures from Colin Barker, Jan 10 2019: (Start)

G.f.: x*(8 + 167*x + 397*x^2 + 147*x^3 + x^4) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)