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A185489 Number of (n+1) X 2 binary arrays with every 2 X 2 subblock sum equal to some horizontal or vertical neighbor 2 X 2 subblock sum. 2
0, 24, 36, 160, 380, 1332, 3616, 11828, 33764, 107240, 314028, 980996, 2915008, 9013892, 27021076, 83023720, 250222428, 765753844, 2315518240, 7068457300, 21417487492, 65277991272, 198042102732, 603022088996, 1830890468736 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 1 of A185497.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 3*a(n-2) - 14*a(n-3) + 24*a(n-4) - 16*a(n-5) - 24*a(n-6) + 16*a(n-7) - 64*a(n-8).
Empirical g.f.: 4*x^2*(6 - 9*x - 5*x^2 + 32*x^3 - 90*x^4 + 60*x^5 - 96*x^6) / ((1 - 2*x)*(1 - x - 5*x^2 + 4*x^3 - 16*x^4 - 16*x^5 - 8*x^6 - 32*x^7)). - Colin Barker, Feb 27 2018
EXAMPLE
Some solutions for 4 X 2:
..0..1....1..1....1..0....0..1....0..0....0..1....0..1....0..0....1..1....1..0
..0..1....0..1....1..0....1..1....0..0....0..0....0..1....1..1....1..1....0..0
..1..0....1..1....1..0....1..0....0..0....1..0....0..1....0..0....1..1....1..0
..0..1....0..1....0..1....1..1....0..0....0..0....1..0....1..1....1..1....0..0
CROSSREFS
Cf. A185497.
Sequence in context: A327946 A288949 A108190 * A303884 A304616 A172424
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 29 2011
STATUS
approved

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Last modified July 22 00:58 EDT 2024. Contains 374478 sequences. (Running on oeis4.)