A245161 Number of length n 0..6 arrays with new values introduced in order from both ends.

1, 1, 2, 4, 9, 23, 65, 199, 654, 2296, 8569, 33825, 140581, 612933, 2795181, 13298407, 65851100, 338654554, 1805083341, 9952373825, 56645932971, 332111798479, 2000990363889, 12357518954759, 78010845456554, 501994699807228

Offset: 1

Author

R. H. Hardin, Jul 12 2014

Keywords

• nonn

Examples

			Some solutions for n=7:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....1....1....1....1....1....0....1....1....1....1....0....1....1
..0....1....1....1....1....0....1....0....0....2....2....2....1....0....0....1
..1....1....0....0....2....1....2....1....1....2....2....2....0....1....2....0
..0....0....1....1....1....0....1....2....1....0....1....2....0....1....1....0
..0....1....1....0....0....1....1....1....1....1....1....1....0....0....0....1
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
		

Links

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

Crossrefs

Column 6 of A245163.

Formula

Empirical: a(n) = 37*a(n-1) - 605*a(n-2) + 5765*a(n-3) - 35523*a(n-4) + 148371*a(n-5) - 427775*a(n-6) + 849335*a(n-7) - 1134976*a(n-8) + 969292*a(n-9) - 474720*a(n-10) + 100800*a(n-11) for n>12.

Empirical g.f.: x*(1 - 36*x + 570*x^2 - 5230*x^3 + 30829*x^4 - 122268*x^5 + 332049*x^6 - 616386*x^7 + 767435*x^8 - 616428*x^9 + 296529*x^10 - 69446*x^11) / ((1 - x)^2*(1 - 2*x)^2*(1 - 3*x)^2*(1 - 4*x)^2*(1 - 5*x)^2*(1 - 7*x)). - Colin Barker, Nov 03 2018