A283952 Number of 3Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.

0, 0, 87, 906, 7988, 69468, 575456, 4604744, 36137513, 279163040, 2128757750, 16067783050, 120264121036, 893798288058, 6602798852295, 48525145143750, 355015663432086, 2587074206224930, 18786624241231104, 135997998678920894

Offset

1,3

Comments

Row 3 of A283950.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -15*a(n-2) +50*a(n-3) -483*a(n-4) -688*a(n-5) -2954*a(n-6) -1998*a(n-7) +1187*a(n-8) +9770*a(n-9) +26575*a(n-10) +21254*a(n-11) -469*a(n-12) -42264*a(n-13) -80523*a(n-14) -54448*a(n-15) +18704*a(n-16) +71312*a(n-17) +57531*a(n-18) +12848*a(n-19) -15198*a(n-20) -17226*a(n-21) -8382*a(n-22) -2048*a(n-23) +107*a(n-24) +234*a(n-25) +59*a(n-26) +4*a(n-27) -4*a(n-28)

Example

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

Crossrefs

Cf. A283950.

Sequence in context: A220055 A281806 A128956 * A294907 A093287 A231218

Adjacent sequences: A283949 A283950 A283951 * A283953 A283954 A283955

Keyword

nonn

Author

R. H. Hardin, Mar 18 2017

Status

approved