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A183338 Number of n X 6 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally. 1
1, 9, 23, 51, 175, 513, 1397, 4133, 12075, 34521, 100047, 290287, 838039, 2423841, 7016381, 20290449, 58686583, 169784637, 491117363, 1420584719, 4109370831, 11887034385, 34384871493, 99464136973, 287716480627, 832264983105 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Equivalent to all 1s connected only in 2 X 2 blocks.
Column 6 of A183342.
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) + 9*a(n-3) + 6*a(n-4) - 3*a(n-5) - 10*a(n-6) - 17*a(n-7) - 7*a(n-8) + 12*a(n-9) + 12*a(n-10) - 6*a(n-11).
Empirical g.f.: x*(1 + 8*x + 12*x^2 + x^3 - 9*x^4 - 22*x^5 - 26*x^6 + 5*x^7 + 24*x^8 + 6*x^9 - 6*x^10) / (1 - x - 2*x^2 - 9*x^3 - 6*x^4 + 3*x^5 + 10*x^6 + 17*x^7 + 7*x^8 - 12*x^9 - 12*x^10 + 6*x^11). - Colin Barker, Mar 27 2018
EXAMPLE
Some solutions for 5 X 6:
0 0 0 0 1 1 0 0 0 0 0 0 1 1 0 0 1 1 0 1 1 0 1 1
1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 1 0 1 1
1 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 1 1 0
0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 1 1 0
CROSSREFS
Cf. A183342.
Sequence in context: A296311 A159221 A079040 * A212676 A211478 A147420
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2011
STATUS
approved

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Last modified May 25 14:28 EDT 2024. Contains 372788 sequences. (Running on oeis4.)