A281406 Number of 7Xn 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, 2692, 10226, 17194, 30959, 51940, 84474, 129934, 192666, 283820, 424420, 643532, 984928, 1523312, 2366752, 3680140, 5732310, 8944680, 13964678, 21804068, 34052814, 53174028, 82984728, 129437616, 201787582, 314380720, 489483020

Offset

1,2

Comments

Row 7 of A281400.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -6*a(n-2) +6*a(n-3) -7*a(n-4) +6*a(n-5) -3*a(n-6) +4*a(n-7) -7*a(n-8) +6*a(n-9) -4*a(n-10) +4*a(n-11) -2*a(n-12) -a(n-14) +2*a(n-15) -a(n-16) for n>31

Example

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

Crossrefs

Cf. A281400.

Sequence in context: A185748 A252404 A020424 * A111027 A245529 A210049

Adjacent sequences: A281403 A281404 A281405 * A281407 A281408 A281409

Keyword

nonn

Author

R. H. Hardin, Jan 21 2017

Status

approved