A281949 Number of nX2 0..1 arrays with no element unequal to more than four of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

2, 8, 30, 112, 420, 1576, 5912, 22176, 83184, 312032, 1170464, 4390528, 16469312, 61778048, 231735680, 869263872, 3260696320, 12231200256, 45880463872, 172102240256, 645572834304, 2421608712192, 9083698141184, 34073866477568

Offset

1,1

Comments

Column 2 of A281955.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -2*a(n-2) +4*a(n-3)

Example

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

Crossrefs

Cf. A281955.

Sequence in context: A077839 A052530 A274798 * A162551 A073663 A266319

Adjacent sequences: A281946 A281947 A281948 * A281950 A281951 A281952

Keyword

nonn

Author

R. H. Hardin, Feb 03 2017

Status

approved