A186895 - OEIS

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A186895

Number of (n+1)X3 binary arrays with every 2X2 subblock determinant equal to exactly one or two horizontal and vertical neighbor 2X2 subblock determinants

30, 148, 140, 406, 1246, 3106, 7240, 19040, 49004, 124974, 318420, 814714, 2080852, 5324036, 13622742, 34838372, 89070962, 227812618, 582742964, 1490551186, 3812248194, 9750367192, 24938804546, 63787545162, 163151712528, 417295494174

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 2 of A186902

LINKS

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

FORMULA

Empirical: a(n)=a(n-1)+a(n-2)+4*a(n-3)+9*a(n-4)+9*a(n-5)+a(n-6)-26*a(n-7)-50*a(n-8)-58*a(n-9)-32*a(n-10)-17*a(n-11)-a(n-12)+14*a(n-13)+61*a(n-14)+66*a(n-15)+50*a(n-16)+13*a(n-17) for n>19

EXAMPLE

Some solutions for 5X3

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

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

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

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

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

CROSSREFS

Sequence in context: A124958 A126417 A135175 * A185480 A316459 A342483

Adjacent sequences: A186892 A186893 A186894 * A186896 A186897 A186898

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 28 2011

STATUS

approved