A281694 Number of 2Xn 0..2 arrays with no element equal to more than one 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, 0, 6, 272, 2516, 19168, 120824, 692320, 3728304, 19162048, 95114144, 459530496, 2172420416, 10088686592, 46160383360, 208560904704, 932182234880, 4127576462336, 18126823531008, 79031039336448, 342350615184384

Offset

1,3

Comments

Row 2 of A281693.

Links

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

Formula

Empirical: a(n) = 12*a(n-1) -54*a(n-2) +136*a(n-3) -324*a(n-4) +720*a(n-5) -1064*a(n-6) +1632*a(n-7) -2208*a(n-8) +2048*a(n-9) -1920*a(n-10) +1536*a(n-11) -512*a(n-12) for n>15

Example

Some solutions for n=4
..0..0..1..0. .0..1..2..1. .0..0..0..1. .0..1..1..1. .0..1..2..2
..2..2..0..2. .2..0..0..0. .0..2..1..1. .1..2..2..0. .1..1..0..2

Crossrefs

Cf. A281693.

Sequence in context: A193983 A348701 A233234 * A250390 A284071 A254628

Adjacent sequences: A281691 A281692 A281693 * A281695 A281696 A281697

Keyword

nonn

Author

R. H. Hardin, Jan 27 2017

Status

approved