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A198600
Number of 2nX8 0..3 arrays with values 0..3 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors
1
5, 251, 14396, 844228, 49726877, 2934981667, 173328303620, 10237927785188, 604754378402213, 35723495136378379, 2110237768703448092, 124654981592741709892, 7363565234193825044093, 434977425639969487046579
OFFSET
1,1
COMMENTS
Column 4 of A198604
LINKS
FORMULA
Empirical: a(n) = 94*a(n-1) -2472*a(n-2) +26290*a(n-3) -106866*a(n-4) -1801330*a(n-5) +40729156*a(n-6) -223342414*a(n-7) -200031477*a(n-8) +13909482168*a(n-9) -152932111488*a(n-10) -38568285016*a(n-11) +3794102845096*a(n-12) -15877251448552*a(n-13) +179001066971856*a(n-14) +749726254183368*a(n-15) -3840103132751106*a(n-16) -11600962781302492*a(n-17) -91016932033881232*a(n-18) -458001803793712292*a(n-19) -247548236746323660*a(n-20) +9521997841428108260*a(n-21) +49820044145126615544*a(n-22) +79886883079805050620*a(n-23) +246623390473772582478*a(n-24) -1003653798888282353640*a(n-25) -12074335096573425025728*a(n-26) -20437597834240573029240*a(n-27) +10115143348045067085672*a(n-28) +128730639595221044423352*a(n-29) +774430306430662210742928*a(n-30) +1029404581136490556096488*a(n-31) +20780569861354405322307*a(n-32) -12866611310169952404368466*a(n-33) -24621435118644683004279432*a(n-34) +30312576901918725416025282*a(n-35) +58118594917824732421767726*a(n-36) +12738874813992604339260606*a(n-37) +23859029418104532950240868*a(n-38) -31321623314851938873013086*a(n-39) -58149737003040059690390169*a(n-40)
EXAMPLE
Some solutions for n=3
..0..0..1..1..0..0..2..2....0..0..1..1..2..2..2..2....0..0..1..1..0..0..2..2
..0..0..1..1..0..0..2..2....0..0..1..1..2..1..1..2....0..0..1..1..0..0..2..2
..1..1..3..3..2..2..1..1....2..2..3..3..2..1..1..2....2..2..3..3..3..3..1..1
..1..1..3..3..2..2..1..1....2..2..3..3..2..2..2..2....2..2..3..0..0..3..1..1
..2..2..1..1..3..3..0..0....3..3..2..2..1..1..0..0....1..1..3..0..0..3..2..2
..2..2..1..1..3..3..0..0....3..3..2..2..1..1..0..0....1..1..3..3..3..3..2..2
CROSSREFS
Sequence in context: A115739 A142202 A042219 * A213446 A276485 A308295
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 27 2011
STATUS
approved