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A183341 Number of nX9 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally 1
1, 28, 109, 380, 2450, 12075, 55471, 286079, 1429824, 6989477, 34856362, 173451524, 858586095, 4263159553, 21172762001, 105041615196, 521348098233, 2587930504660, 12843811121650, 63746482751185, 316398514788731 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Equivalent to all 1s connected only in 2X2 blocks

Column 9 of A183342

LINKS

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

FORMULA

Empirical: a(n)=a(n-1)+4*a(n-2)+66*a(n-3)+95*a(n-4)+43*a(n-5)-720*a(n-6)-1911*a(n-7)-1442*a(n-8)+3264*a(n-9)+10821*a(n-10)+19141*a(n-11)+2814*a(n-12)-66628*a(n-13)-89804*a(n-14)+31181*a(n-15)+153550*a(n-16)+92838*a(n-17)+40230*a(n-18)-70110*a(n-19)-229684*a(n-20)-107631*a(n-21)-94711*a(n-22)+28881*a(n-23)+390574*a(n-24)+124645*a(n-25)-26599*a(n-26)-25097*a(n-27)-277598*a(n-28)+259486*a(n-29)+159878*a(n-30)-12870*a(n-31)-21470*a(n-32)-444709*a(n-33)-78037*a(n-34)-123573*a(n-35)+71536*a(n-36)+64021*a(n-37)-594*a(n-38)+19314*a(n-39)-12660*a(n-40)+3610*a(n-41)+920*a(n-42)-1448*a(n-43)+704*a(n-44)-128*a(n-45)

EXAMPLE

Some solutions for 5X9

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

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

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

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

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

CROSSREFS

Sequence in context: A068196 A044279 A044660 * A118613 A245153 A295981

Adjacent sequences:  A183338 A183339 A183340 * A183342 A183343 A183344

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 04 2011

STATUS

approved

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Last modified September 27 22:36 EDT 2020. Contains 337388 sequences. (Running on oeis4.)