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 A269897 Number of n X 3 0..6 arrays with some element plus some horizontally or vertically adjacent neighbor totalling six exactly once. 1

%I #8 Jan 29 2019 15:06:58

%S 84,45360,12377400,2801265390,579818225700,113873466835170,

%T 21603218450171400,3998999827651729950,726818744373948859500,

%U 130236638797904930468730,23073817637719546502490000

%N Number of n X 3 0..6 arrays with some element plus some horizontally or vertically adjacent neighbor totalling six exactly once.

%H R. H. Hardin, <a href="/A269897/b269897.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 330*a(n-1) - 28773*a(n-2) + 255420*a(n-3) - 599076*a(n-4) for n>5.

%F Empirical g.f.: 42*x*(2 + 420*x - 4154*x^2 + 9795*x^3 + 1152*x^4) / (1 - 165*x + 774*x^2)^2. - _Colin Barker_, Jan 29 2019

%e Some solutions for n=2:

%e ..0..3..1. .2..0..3. .2..1..4. .4..5..0. .5..3..4. .0..4..3. .3..6..4

%e ..4..4..5. .3..6..1. .2..0..2. .3..3..1. .3..6..2. .2..4..4. .4..1..2

%Y Column 3 of A269902.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 07 2016

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Last modified June 9 13:49 EDT 2023. Contains 363180 sequences. (Running on oeis4.)