A281568 Number of 6Xn 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 310, 18020, 53568, 154722, 347316, 692421, 1275888, 2241388, 3864672, 6600534, 11152312, 18730106, 31334466, 52215554, 86771200, 143873022, 237945548, 392609350, 646423526, 1062014984, 1741176780, 2849127546, 4653300102

Offset

1,2

Comments

Row 6 of A281563.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -15*a(n-2) +23*a(n-3) -30*a(n-4) +36*a(n-5) -31*a(n-6) +12*a(n-7) +9*a(n-8) -23*a(n-9) +33*a(n-10) -36*a(n-11) +23*a(n-12) -3*a(n-13) -9*a(n-14) +12*a(n-15) -12*a(n-16) +9*a(n-17) -2*a(n-18) -3*a(n-19) +3*a(n-20) -a(n-21) for n>37

Example

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

Crossrefs

Cf. A281563.

Sequence in context: A237697 A218103 A289304 * A084876 A190567 A376235

Adjacent sequences: A281565 A281566 A281567 * A281569 A281570 A281571

Keyword

nonn

Author

R. H. Hardin, Jan 24 2017

Status

approved