A268627 Number of nX7 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totalling two no more than once.

768, 29646, 982086, 30553014, 915847266, 26758514760, 767057092212, 21665715966234, 604770363515718, 16719464029955466, 458539471622171262, 12491032205839395768, 338309651358216576312, 9117289065936178169226

Offset: 1

Author

R. H. Hardin, Feb 09 2016

Keywords

• nonn

Comments

Column 7 of A268628.

Examples

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

Links

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

Crossrefs

Cf. A268628.

Formula

Empirical: a(n) = 110*a(n-1) -5243*a(n-2) +144650*a(n-3) -2610593*a(n-4) [phone]*a(n-5) -305811128*a(n-6) [phone]*a(n-7) -11513372884*a(n-8) [phone]*a(n-9) -161412354008*a(n-10) [phone]*a(n-11) -901108804624*a(n-12) [phone]*a(n-13) -2035022988048*a(n-14) [phone]*a(n-15) -1815145078160*a(n-16) [phone]*a(n-17) -603502277248*a(n-18) [phone]*a(n-19) -68574152448*a(n-20) [phone]*a(n-21) -2352277504*a(n-22) [phone]*a(n-23) -19140608*a(n-24) +835584*a(n-25) -16384*a(n-26)