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A274800
Number of n X 5 0..2 arrays with no element equal to any value at offset (-1,-2) (-2,-1) (0,-1) or (-1,0) and new values introduced in order 0..2.
1
8, 60, 420, 3104, 22988, 169328, 1252608, 9243332, 68301192, 504334580, 3725379284, 27513045320, 203212320508, 1500856265992, 11085101613680, 81871796085532, 604688931568808, 4466096896968716, 32985652382855332
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + 35*a(n-2) + 42*a(n-3) - 41*a(n-4) - 60*a(n-5) - 23*a(n-6) - 2*a(n-7).
Empirical g.f.: 4*x*(2 + 11*x + 5*x^2 - 43*x^3 - 28*x^4 + 3*x^5 + 2*x^6) / (1 - 2*x - 35*x^2 - 42*x^3 + 41*x^4 + 60*x^5 + 23*x^6 + 2*x^7). - Colin Barker, Jan 31 2019
EXAMPLE
Some solutions for n=4:
..0..1..0..1..2. .0..1..2..1..0. .0..1..2..1..2. .0..1..0..1..0
..1..0..1..2..1. .1..0..1..2..1. .2..0..1..0..1. .1..2..1..2..1
..2..1..0..1..2. .0..1..2..1..0. .1..2..0..1..0. .0..1..2..1..2
..1..0..1..0..1. .2..0..1..2..1. .2..0..2..0..1. .1..0..1..2..1
CROSSREFS
Column 5 of A274803.
Sequence in context: A159727 A081158 A002927 * A126640 A093132 A094169
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 07 2016
STATUS
approved