A283779 Number of nX3 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, 5, 60, 745, 7298, 62303, 496884, 3767599, 27544383, 195862137, 1362432578, 9309699590, 62681109851, 416796696040, 2742095941841, 17874537516228, 115580492689760, 742070620542530, 4734351638158905, 30034414798026318

Offset

1,2

Comments

Column 3 of A283784.

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -69*a(n-2) +107*a(n-3) -309*a(n-4) +1218*a(n-5) -502*a(n-6) +4740*a(n-7) -5256*a(n-8) +3491*a(n-9) -27390*a(n-10) +288*a(n-11) -31284*a(n-12) +59157*a(n-13) +45831*a(n-14) +125150*a(n-15) +14523*a(n-16) -89694*a(n-17) -228321*a(n-18) -273708*a(n-19) -34062*a(n-20) +168784*a(n-21) +436860*a(n-22) +297456*a(n-23) +20424*a(n-24) -252768*a(n-25) -337248*a(n-26) -116736*a(n-27) +40320*a(n-28) +115200*a(n-29) +64000*a(n-30)

Example

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

Crossrefs

Cf. A283784.

Sequence in context: A099672 A320361 A138134 * A353875 A370445 A093885

Adjacent sequences: A283776 A283777 A283778 * A283780 A283781 A283782

Keyword

nonn

Author

R. H. Hardin, Mar 16 2017

Status

approved