A281650 Number of nX4 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

2, 400, 7986, 135444, 2159590, 32771472, 483655876, 6987992320, 99358947608, 1395010709860, 19387305130218, 267179720941768, 3656156025688492, 49732278903615588, 672986584493901470, 9066096794997480688

Offset

1,1

Comments

Column 4 of A281653.

Links

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

Formula

Empirical: a(n) = 26*a(n-1) -163*a(n-2) -252*a(n-3) +2003*a(n-4) +3540*a(n-5) -3665*a(n-6) -21804*a(n-7) -50091*a(n-8) -16676*a(n-9) +102064*a(n-10) +103800*a(n-11) +42777*a(n-12) -28852*a(n-13) -138546*a(n-14) +272762*a(n-15) -25872*a(n-16) -879144*a(n-17) +249945*a(n-18) +514090*a(n-19) -431504*a(n-20) +81404*a(n-21) +293927*a(n-22) +131582*a(n-23) +143*a(n-24) -73224*a(n-25) -55435*a(n-26) -40960*a(n-27) -21076*a(n-28) -7894*a(n-29) -2713*a(n-30) -598*a(n-31) -169*a(n-32) for n>37

Example

Some solutions for n=4
..0..1..0..1. .0..0..1..0. .0..1..2..0. .0..1..1..0. .0..0..1..1
..0..1..1..1. .2..0..2..1. .2..0..2..0. .2..1..2..0. .2..1..2..0
..0..1..2..0. .2..1..2..0. .1..0..1..2. .0..1..0..1. .0..0..2..1
..0..2..0..1. .0..0..2..0. .2..2..0..0. .0..2..2..1. .1..1..2..1

Crossrefs

Cf. A281653.

Sequence in context: A249177 A249178 A375843 * A324403 A214597 A283661

Adjacent sequences: A281647 A281648 A281649 * A281651 A281652 A281653

Keyword

nonn

Author

R. H. Hardin, Jan 26 2017

Status

approved