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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
 84, 45360, 12377400, 2801265390, 579818225700, 113873466835170, 21603218450171400, 3998999827651729950, 726818744373948859500, 130236638797904930468730, 23073817637719546502490000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 330*a(n-1) - 28773*a(n-2) + 255420*a(n-3) - 599076*a(n-4) for n>5. 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 EXAMPLE Some solutions for n=2: ..0..3..1. .2..0..3. .2..1..4. .4..5..0. .5..3..4. .0..4..3. .3..6..4 ..4..4..5. .3..6..1. .2..0..2. .3..3..1. .3..6..2. .2..4..4. .4..1..2 CROSSREFS Column 3 of A269902. Sequence in context: A269933 A184126 A185403 * A184896 A203093 A290274 Adjacent sequences: A269894 A269895 A269896 * A269898 A269899 A269900 KEYWORD nonn AUTHOR R. H. Hardin, Mar 07 2016 STATUS approved

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Last modified March 23 23:09 EDT 2023. Contains 361454 sequences. (Running on oeis4.)