A283786 Number of 3Xn 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.

0, 1, 60, 625, 5432, 43793, 336614, 2456405, 17337452, 119568097, 807400279, 5361533627, 35121018814, 227356916503, 1456991303945, 9255597126444, 58345386218659, 365301459240939, 2273330797518109, 14070544563651381

Offset

1,3

Comments

Row 3 of A283784.

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -66*a(n-2) +80*a(n-3) -468*a(n-4) +3087*a(n-5) -2637*a(n-6) +1521*a(n-7) -48147*a(n-8) +47343*a(n-9) +81669*a(n-10) +252723*a(n-11) -449826*a(n-12) -859263*a(n-13) +209880*a(n-14) +2012553*a(n-15) +1838166*a(n-16) -3525918*a(n-17) -3408930*a(n-18) +1213335*a(n-19) +5670018*a(n-20) +961731*a(n-21) -5692641*a(n-22) -258915*a(n-23) +1572148*a(n-24) +2087043*a(n-25) -2057643*a(n-26) -530461*a(n-27) +1830090*a(n-28) -1416102*a(n-29) +615644*a(n-30) -172620*a(n-31) +29400*a(n-32) -2744*a(n-33)

Example

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

Crossrefs

Cf. A283784.

Sequence in context: A229750 A223338 A081384 * A099344 A324068 A223242

Adjacent sequences: A283783 A283784 A283785 * A283787 A283788 A283789

Keyword

nonn

Author

R. H. Hardin, Mar 16 2017

Status

approved