A281475 Number of 7 X n 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.

64, 2785, 634, 897, 1106, 1422, 1887, 2429, 3093, 4063, 5629, 8037, 11711, 17407, 26039, 38977, 58581, 88383, 133531, 201957, 305881, 463585, 702653, 1065249, 1615351, 2449669, 3715009, 5634375, 8545763, 12961559, 19659317, 29818565

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-3) - a(n-4) + a(n-7) - a(n-8) for n>16.

Empirical g.f.: x*(64 + 2657*x - 4872*x^2 + 2350*x^3 - 2775*x^4 + 2258*x^5 - 114*x^6 - 196*x^7 - 2915*x^8 + 1992*x^9 - 209*x^10 - 31*x^11 - 20*x^12 - 9*x^13 - 14*x^14 - 32*x^15) / ((1 - x)*(1 - x - x^3 - x^7)). - Colin Barker, Feb 20 2019

Example

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

Crossrefs

Row 7 of A281469.

Sequence in context: A036531 A301840 A302068 * A302628 A302420 A303187

Adjacent sequences: A281472 A281473 A281474 * A281476 A281477 A281478

Keyword

nonn

Author

R. H. Hardin, Jan 22 2017

Status

approved