A163038 Number of nX3 binary arrays with all 1s connected and a path of 1s from left column to right column.

1, 17, 144, 920, 5191, 27651, 143342, 733512, 3730303, 18914231, 95766768, 484557538, 2450951157, 12395284963, 62682479764, 316971668262, 1602829696167, 8104958759329, 40983832221302, 207239970377650, 1047934399198859

Offset: 1

Author

R. H. Hardin Jul 20 2009

Keywords

• nonn

Links

• R. H. Hardin, Table of n, a(n) for n=1..62

Formula

Empirical: a(n)= 12*a(n-1) -54*a(n-2) +121*a(n-3) -144*a(n-4) +72*a(n-5) +38*a(n-6) -82*a(n-7) +41*a(n-8) +4*a(n-9) -8*a(n-10) +a(n-11). G.f.: -x*(1+5*x-6*x^2-11*x^3+14*x^4-9*x^5-2*x^6-x^7+x^8) /( (x^2+2*x-1) *(x^6-7*x^5 +x^4+6*x^3-11*x^2+7*x-1) *(x-1)^3). [From R. J. Mathar, Aug 11 2009]