A200661 Number of 0..1 arrays x(0..n-1) of n elements with each no smaller than the sum of its three previous neighbors modulo 2.

2, 3, 5, 8, 12, 17, 25, 36, 51, 72, 102, 144, 202, 284, 399, 560, 785, 1101, 1544, 2164, 3033, 4251, 5958, 8349, 11700, 16396, 22976, 32196, 45116, 63221, 88590, 124139, 173953, 243756, 341568, 478629, 670689, 939816, 1316935, 1845380, 2585874

Offset: 1

Author

R. H. Hardin, Nov 20 2011

Keywords

• nonn

Comments

Column 1 of A200668.

Examples

			Some solutions for n=6:
..0....0....0....0....0....1....0....0....0....1....1....1....0....0....1....0
..0....0....0....0....0....1....1....1....1....1....1....1....0....1....1....0
..0....1....0....0....1....0....1....1....1....0....0....0....0....1....1....1
..1....1....1....0....1....1....0....0....0....0....1....1....0....1....1....1
..1....0....1....0....1....1....0....1....1....1....0....1....0....1....1....0
..0....1....1....1....1....1....1....0....1....1....1....0....0....1....1....0
		

Links

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

Crossrefs

Cf. A200668.

Formula

Empirical: a(n)=a(n-1)+a(n-2)-a(n-5)-a(n-6)+a(n-7).

Empirical g.f.: x*(1 + x^2)*(2 + x - 2*x^2 - x^3 + x^4) / ((1 - x)*(1 - x^2 - x^3 - x^4 + x^6)). - Colin Barker, May 21 2018