A317858 Number of nX3 0..1 arrays with every element unequal to 1, 2 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 6, 4, 19, 32, 72, 164, 331, 790, 1700, 3879, 8689, 19763, 44787, 101708, 232136, 528496, 1206975, 2755982, 6298876, 14399412, 32932776, 75341117, 172383450, 394513860, 902958422, 2066919648, 4731632878, 10832452949, 24800620478

Offset

1,2

Comments

Column 3 of A317863.

Links

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

Formula

Empirical: a(n) = 5*a(n-2) +8*a(n-3) -2*a(n-4) -26*a(n-5) -32*a(n-6) +6*a(n-7) +40*a(n-8) +32*a(n-9) -3*a(n-10) -16*a(n-11) +17*a(n-12) +6*a(n-13) -20*a(n-14) -6*a(n-15) +19*a(n-16) +14*a(n-17) -14*a(n-19) -5*a(n-20) +2*a(n-21) -10*a(n-22) +3*a(n-24) +a(n-26) for n>32

Example

Some solutions for n=5
..0..1..0. .0..1..1. .0..1..0. .0..0..0. .0..1..1. .0..1..0. .0..1..0
..0..0..1. .0..1..0. .0..0..0. .1..1..0. .1..1..0. .1..1..0. .1..1..0
..1..1..1. .0..0..0. .1..0..1. .1..0..1. .1..1..1. .0..0..0. .1..1..0
..1..0..0. .1..0..1. .0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..0..0
..0..1..0. .0..0..0. .0..1..0. .0..0..0. .1..0..1. .1..0..1. .0..1..0

Crossrefs

Cf. A317863.

Sequence in context: A213761 A160248 A356044 * A375673 A212891 A107983

Adjacent sequences: A317855 A317856 A317857 * A317859 A317860 A317861

Keyword

nonn

Author

R. H. Hardin, Aug 09 2018

Status

approved