This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A163038 #7 Jul 22 2025 06:58:42 %S A163038 1,17,144,920,5191,27651,143342,733512,3730303,18914231,95766768, %T A163038 484557538,2450951157,12395284963,62682479764,316971668262, %U A163038 1602829696167,8104958759329,40983832221302,207239970377650,1047934399198859 %N A163038 Number of nX3 binary arrays with all 1s connected and a path of 1s from left column to right column. %H A163038 R. H. Hardin, <a href="/A163038/b163038.txt">Table of n, a(n) for n=1..62</a> %F A163038 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] %K A163038 nonn %O A163038 1,2 %A A163038 _R. H. Hardin_ Jul 20 2009