A280806 Number of nX4 0..1 arrays with no element equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 18, 332, 2146, 9715, 37644, 133067, 440282, 1387898, 4213683, 12419791, 35750871, 100948088, 280549719, 769389206, 2086323089, 5602827011, 14920267585, 39440232733, 103577644060, 270436207834, 702418367935

Offset

1,2

Comments

Column 4 of A280810.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -39*a(n-2) +72*a(n-3) -57*a(n-4) +12*a(n-5) -31*a(n-6) +61*a(n-7) +39*a(n-8) -148*a(n-9) +58*a(n-10) +72*a(n-11) +2*a(n-12) -92*a(n-13) -33*a(n-14) +142*a(n-15) -25*a(n-16) -90*a(n-17) +22*a(n-18) +50*a(n-19) +3*a(n-20) -47*a(n-21) +5*a(n-22) +30*a(n-23) -12*a(n-24) -9*a(n-25) +6*a(n-26) +a(n-27) -a(n-28) for n>36

Example

Some solutions for n=4
..0..0..1..0. .0..1..0..0. .0..1..0..1. .0..0..1..0. .0..0..0..0
..0..1..0..1. .1..0..1..1. .0..1..0..1. .1..0..0..1. .1..1..1..1
..0..1..0..0. .0..0..0..0. .1..1..0..0. .0..1..1..1. .0..0..1..0
..1..0..1..1. .1..1..1..1. .0..0..1..1. .1..0..0..0. .1..0..0..0

Crossrefs

Cf. A280810.

Sequence in context: A041614 A222812 A166787 * A068771 A039646 A212669

Adjacent sequences: A280803 A280804 A280805 * A280807 A280808 A280809

Keyword

nonn

Author

R. H. Hardin, Jan 08 2017

Status

approved