A245136 Number of length 6 0..n arrays least squares fitting to a zero slope straight line, with a single point taken as having zero slope.

8, 43, 172, 505, 1248, 2687, 5220, 9385, 15868, 25539, 39428, 58805, 85144, 120163, 165900, 224593, 298832, 391539, 505928, 645645, 814656, 1017335, 1258484, 1543341, 1877624, 2267451, 2719516, 3240965, 3839476, 4523383, 5301420, 6183009

Offset: 1

Author

R. H. Hardin, Jul 12 2014

Keywords

• nonn

Examples

			Some solutions for n=10
..7....9....8....6....7....7....6....3....3....0....0....3....4....2....2....6
.10....0....3....2....9....9...10....0....6....9....6....0....7....4....7....4
..2....8....2....9....7...10....3....4....8....1....9....6....0....1...10....9
..8....3....3...10....2....4....0....0....6....8....0....1....5....0....4....0
..3...10....1....0....9....6....6....3...10....5....9....5....2....1....4....2
.10....4....9....7....8...10....9....2....1....1....0....1....6....4....5....9
		

Links

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

Crossrefs

Row 6 of A245134.

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -4*a(n-4) +4*a(n-5) -5*a(n-6) +4*a(n-7) -5*a(n-8) +8*a(n-9) -5*a(n-10) +4*a(n-11) -5*a(n-12) +4*a(n-13) -4*a(n-14) +2*a(n-15) -a(n-16) +2*a(n-17) -a(n-18).

Empirical g.f.: -x*(-8 -27*x -94*x^2 -188*x^3 -356*x^4 -492*x^5 -640*x^6 -651*x^7 -644*x^8 -492*x^9 -356*x^10 -187*x^11 -96*x^12 -24*x^13 -8*x^14 -2*x^16 +x^17) / ( (1+x+x^2)^2*(x^4+x^3+x^2+x+1)^2*(x-1)^6 ). - R. J. Mathar, Jul 12 2014