A186896 - OEIS

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A186896

Number of (n+1)X4 binary arrays with every 2X2 subblock determinant equal to exactly one or two horizontal and vertical neighbor 2X2 subblock determinants

76, 140, 444, 1692, 3948, 13894, 35270, 122820, 328174, 1091770, 2989514, 9789230, 27386704, 88043136, 249821778, 792963658, 2277817920, 7153114096, 20739269674, 64581466696, 188672537578, 583564854384, 1715136004208, 5276315756596

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

OFFSET

1,1

COMMENTS

Column 3 of A186902

LINKS

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

FORMULA

Empirical: a(n)=8*a(n-2)+4*a(n-3)+10*a(n-4)-3*a(n-5)-73*a(n-6)-106*a(n-7)-22*a(n-8)+143*a(n-9)+154*a(n-10)+94*a(n-11)-115*a(n-12)-74*a(n-13)+33*a(n-14)+120*a(n-15)-30*a(n-16)-30*a(n-17)-8*a(n-18)+22*a(n-19)-12*a(n-20)-2*a(n-21)-4*a(n-22)+4*a(n-23) for n>29

EXAMPLE

Some solutions for 3X4

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

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

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

CROSSREFS

Sequence in context: A092890 A261705 A248532 * A202173 A004924 A004944

Adjacent sequences: A186893 A186894 A186895 * A186897 A186898 A186899

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 28 2011

STATUS

approved