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, 110, 2990, 127570, 4403225, 167398110, 6079401960, 225574291125, 8285469213945, 305786452982260, 11260066599241195, 415073544779136460, 15292958690004125565, 563586551260018728505, 20767361004817999220125

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