A281606 Number of 3Xn 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.
5, 50, 209, 1283, 8180, 49572, 302304, 1849212, 11295326, 69003066, 421598546, 2575763454, 15736620000, 96143466614, 587391366384, 3588683849428, 21925168436114, 133952450888038, 818386359248384, 4999955088202190
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..0..1. .0..1..0..1. .0..1..0..2. .0..1..2..1. .0..1..1..0 ..2..1..2..1. .0..1..2..1. .0..2..0..2. .1..2..0..1. .2..0..2..2 ..2..0..2..0. .2..1..0..0. .1..2..0..1. .0..2..0..2. .2..1..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A281605.
Formula
Empirical: a(n) = 6*a(n-1) -4*a(n-2) +29*a(n-3) -15*a(n-4) +73*a(n-5) +11*a(n-6) -32*a(n-7) +6*a(n-8) +a(n-9) -30*a(n-10) -26*a(n-11) +10*a(n-12) +8*a(n-13) for n>15
Comments