A183806 - OEIS

A183806

1/16 the number of (n+1)X5 binary arrays with no 2X2 subblock being a reflection across the shared element pair of any horizontal or vertical neighbor

27, 237, 1953, 16953, 143191, 1232595, 10494847, 89998565, 768481445, 6579905737, 56244325315, 481279798699, 4115586970547, 35208336763197, 301125201891953, 2575843502271345, 22031666094964551, 188453144399278867

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OFFSET

1,1

COMMENTS

Column 4 of A183811

LINKS

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

FORMULA

Empirical: a(n)=6*a(n-1)+81*a(n-2)-425*a(n-3)-1968*a(n-4)+10277*a(n-5)+16576*a(n-6)-92864*a(n-7)-64803*a(n-8)+320262*a(n-9)+224743*a(n-10)-99955*a(n-11)-959780*a(n-12)-1547921*a(n-13)+2262032*a(n-14)+2523060*a(n-15)-1692000*a(n-16)-1053000*a(n-17)

EXAMPLE

Some solutions with upper left block zero for 3X5

..0..0..1..0..0....0..0..1..0..1....0..0..1..1..1....0..0..0..1..1

..0..0..1..1..0....0..0..1..1..0....0..0..1..1..0....0..0..1..0..0

..0..1..0..1..1....1..1..0..0..0....0..1..0..1..0....0..1..1..0..1

CROSSREFS

Sequence in context: A273822 A027500 A069979 * A207104 A075548 A345054

Adjacent sequences: A183803 A183804 A183805 * A183807 A183808 A183809

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 07 2011

STATUS

approved