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A185536 1/6 the number of nX3 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors 1
1, 110, 2990, 127570, 4403225, 167398110, 6079401960, 225574291125, 8285469213945, 305786452982260, 11260066599241195, 415073544779136460, 15292958690004125565, 563586551260018728505, 20767361004817999220125 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A185540

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n)=22*a(n-1)+638*a(n-2)-2567*a(n-3)-29583*a(n-4)+27088*a(n-5)+209637*a(n-6)+620796*a(n-7)-1634411*a(n-8)-4083145*a(n-9)+17086070*a(n-10)-21827225*a(n-11)-42404829*a(n-12)-73933685*a(n-13)+687497360*a(n-14)-669370750*a(n-15)-1844490625*a(n-16)+8145764375*a(n-17)+6297734375*a(n-18)-14443984375*a(n-19)-34831953125*a(n-20)-42570312500*a(n-21)-47656250000*a(n-22)-78125000000*a(n-23)

EXAMPLE

Some solutions for 5X3 with a(1,1)=0

..0..0..0....0..0..0....0..0..3....0..0..3....0..0..0....0..0..0....0..3..3

..0..3..3....0..3..3....0..0..3....0..3..3....0..3..3....0..3..3....0..0..0

..4..0..0....4..1..3....3..3..1....1..0..0....0..2..2....2..2..3....5..2..0

..4..4..4....4..1..0....5..5..1....1..1..2....3..4..2....2..4..0....5..2..2

..5..5..4....0..0..0....4..4..4....5..5..2....3..4..4....2..4..0....5..5..5

CROSSREFS

Sequence in context: A163729 A251020 A245876 * A201833 A035836 A008395

Adjacent sequences:  A185533 A185534 A185535 * A185537 A185538 A185539

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 30 2011

STATUS

approved

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Last modified September 20 13:07 EDT 2020. Contains 337264 sequences. (Running on oeis4.)