A317737 Number of nX4 0..1 arrays with every element unequal to 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

0, 2, 3, 4, 14, 23, 35, 98, 213, 448, 1053, 2285, 5170, 11442, 25631, 57472, 127875, 286908, 640173, 1432260, 3202305, 7156889, 16008863, 35779725, 80013078, 178882627, 399942789, 894243714, 1999266125, 4470164997, 9994288714

Offset

1,2

Comments

Column 4 of A317741.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +3*a(n-3) -2*a(n-4) +a(n-5) -6*a(n-6) +8*a(n-7) -16*a(n-8) -7*a(n-9) -17*a(n-10) +7*a(n-11) +5*a(n-12) +9*a(n-13) +3*a(n-14) +28*a(n-15) +16*a(n-16) +18*a(n-17) -5*a(n-18) -2*a(n-19) -3*a(n-20) -2*a(n-21) -a(n-22) +a(n-23) for n>26

Example

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

Crossrefs

Cf. A317741.

Sequence in context: A333622 A019137 A333623 * A188533 A163128 A280924

Adjacent sequences: A317734 A317735 A317736 * A317738 A317739 A317740

Keyword

nonn

Author

R. H. Hardin, Aug 05 2018

Status

approved