A281399 Number of nX7 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 1296, 2364, 6276, 16241, 37462, 84474, 185834, 400854, 871302, 1899789, 4111556, 8868230, 19130914, 41172419, 88375862, 189462087, 405538634, 866448924, 1848700340, 3939571575, 8383924848, 17820831178, 37839585622, 80261619670

Offset

1,2

Comments

Column 7 of A281400.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -a(n-2) +5*a(n-3) -15*a(n-4) -7*a(n-5) +26*a(n-7) +34*a(n-8) -8*a(n-9) -16*a(n-10) -40*a(n-11) -16*a(n-12) -26*a(n-13) +5*a(n-14) +59*a(n-15) +33*a(n-16) +3*a(n-17) -18*a(n-18) -2*a(n-19) -15*a(n-20) -21*a(n-21) +9*a(n-22) +9*a(n-23) for n>38

Example

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

Crossrefs

Cf. A281400.

Sequence in context: A273631 A186486 A186485 * A043372 A217908 A223508

Adjacent sequences: A281396 A281397 A281398 * A281400 A281401 A281402

Keyword

nonn

Author

R. H. Hardin, Jan 21 2017

Status

approved