A318425 Number of nX3 0..1 arrays with every element unequal to 1, 2, 3 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 16, 36, 147, 417, 1353, 4095, 12853, 39489, 123210, 380280, 1182026, 3659119, 11351061, 35179874, 109070933, 338113844, 1048217069, 3249453631, 10073853147, 31229167798, 96814146538, 300130174990, 930430509302, 2884410320136

Offset

1,2

Comments

Column 3 of A318430.

Links

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

Formula

Empirical: a(n) = 9*a(n-2) +11*a(n-3) -14*a(n-4) -32*a(n-5) -29*a(n-6) -51*a(n-7) +33*a(n-8) +116*a(n-9) +18*a(n-10) +70*a(n-11) +92*a(n-12) -22*a(n-13) -12*a(n-16) +4*a(n-17) for n>20

Example

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

Crossrefs

Cf. A318430.

Sequence in context: A069262 A076956 A075369 * A273373 A264546 A218523

Adjacent sequences: A318422 A318423 A318424 * A318426 A318427 A318428

Keyword

nonn

Author

R. H. Hardin, Aug 26 2018

Status

approved