A268638 Number of n X 7 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totaling two exactly once.

576, 25272, 875592, 27906474, 849572724, 25093766490, 725187096504, 20612084839848, 578250487434612, 16051896344807322, 441734555450215308, 12067989070909055082, 327659984810446438932, 8849194102430720956704

Offset

1,1

Comments

Column 7 of A268639.

Links

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

Formula

Empirical: a(n) = 110*a(n-1) -5243*a(n-2) +144650*a(n-3) -2610593*a(n-4) +33017408*a(n-5) -305811128*a(n-6) +2137462184*a(n-7) -11513372884*a(n-8) +48502300256*a(n-9) -161412354008*a(n-10) +427044616576*a(n-11) -901108804624*a(n-12) +1517344261024*a(n-13) -2035022988048*a(n-14) +2164824966496*a(n-15) -1815145078160*a(n-16) +1189730382208*a(n-17) -603502277248*a(n-18) +234173991424*a(n-19) -68574152448*a(n-20) +14906358784*a(n-21) -2352277504*a(n-22) +260550656*a(n-23) -19140608*a(n-24) +835584*a(n-25) -16384*a(n-26).

Example

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

Crossrefs

Cf. A268639.

Sequence in context: A370226 A354021 A282780 * A230522 A223301 A168660

Adjacent sequences: A268635 A268636 A268637 * A268639 A268640 A268641

Keyword

nonn

Author

R. H. Hardin, Feb 09 2016

Status

approved