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A163705 Number of nX3 binary arrays with all 1s connected, a path of 1s from left column to lower right corner, and no 1 having more than two 1s adjacent 1
1, 7, 28, 80, 200, 469, 1064, 2359, 5144, 11091, 23739, 50569, 107380, 227518, 481337, 1017225, 2148079, 4533560, 9564187, 20170750, 42529933, 89658336, 188985456, 398310426, 839423323, 1768945377, 3727588148, 7854637968, 16550561260 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n=1..50

FORMULA

Empirical: a(n)=6*a(n-1)-13*a(n-2)+11*a(n-3)+a(n-4)-9*a(n-5)+7*a(n-6)-a(n-7)-2*a(n-8)+a(n-9) for n>=12

Empirical: G.f.: -x*(1+x-x^2-8*x^3+6*x^4+3*x^5-2*x^6-4*x^7-4*x^8+2*x^9+2*x^10)/((x^2+x-1) *( x^4+2*x-1) *(x-1)^3). [From R. J. Mathar, Aug 11 2009]

EXAMPLE

All solutions for n=2

...0.0.0...0.0.1...1.0.0...1.0.1...1.1.0...1.1.1...1.1.1

...1.1.1...1.1.1...1.1.1...1.1.1...0.1.1...0.0.1...1.0.1

CROSSREFS

Sequence in context: A061968 A223772 A024012 * A162595 A073363 A247608

Adjacent sequences:  A163702 A163703 A163704 * A163706 A163707 A163708

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 03 2009

STATUS

approved

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Last modified May 8 15:03 EDT 2021. Contains 343666 sequences. (Running on oeis4.)