A317819 Number of nX4 0..1 arrays with every element unequal to 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

2, 50, 135, 702, 2726, 11768, 48526, 203049, 846901, 3533862, 14751288, 61572336, 256988741, 1072703816, 4477368403, 18688452762, 78005403965, 325591740543, 1359014862402, 5672494506043, 23676864307080, 98826717050870

Offset

1,1

Comments

Column 4 of A317823.

Links

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

Formula

Empirical: a(n) = a(n-1) +20*a(n-2) +6*a(n-3) -154*a(n-4) -117*a(n-5) +672*a(n-6) +587*a(n-7) -2050*a(n-8) -1804*a(n-9) +3999*a(n-10) +3942*a(n-11) -2519*a(n-12) -5840*a(n-13) -9009*a(n-14) +8051*a(n-15) +33470*a(n-16) -7813*a(n-17) -52983*a(n-18) -121*a(n-19) +41444*a(n-20) +12853*a(n-21) -6529*a(n-22) -19825*a(n-23) -19439*a(n-24) +13134*a(n-25) +21223*a(n-26) -2212*a(n-27) -10933*a(n-28) -1301*a(n-29) +3458*a(n-30) +557*a(n-31) -769*a(n-32) -110*a(n-33) +103*a(n-34) +19*a(n-35) -11*a(n-36) +a(n-37) for n>43

Example

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

Crossrefs

Cf. A317823.

Sequence in context: A076267 A050800 A231051 * A231082 A318426 A265962

Adjacent sequences: A317816 A317817 A317818 * A317820 A317821 A317822

Keyword

nonn

Author

R. H. Hardin, Aug 07 2018

Status

approved