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 A180763 #6 Mar 26 2018 09:54:52 %S A180763 1,11,63,390,2385,14621,89602,549125,3365327,20624430,126397089, %T A180763 774626021,4747304792,29093913597,178302394173,1092728334730, %U A180763 6696798543441,41041409200977,251522762447718,1541460229095645 %N A180763 Half the number of n X 3 binary arrays with each element equal to at least one neighbor. %C A180763 Column 3 of A180771. %H A180763 R. H. Hardin, <a href="/A180763/b180763.txt">Table of n, a(n) for n=1..99</a> %F A180763 Empirical: a(n) = 5*a(n-1) + 8*a(n-2) - 5*a(n-3) - 10*a(n-4) - a(n-5) + 3*a(n-6) + 4*a(n-7) - 2*a(n-8). %F A180763 Empirical g.f.: x*(1 - x)*(1 + 7*x + 7*x^2 - x^3 - 5*x^4 - 3*x^5 + 2*x^6) / (1 - 5*x - 8*x^2 + 5*x^3 + 10*x^4 + x^5 - 3*x^6 - 4*x^7 + 2*x^8). - _Colin Barker_, Mar 26 2018 %Y A180763 Cf. A180771. %K A180763 nonn %O A180763 1,2 %A A180763 _R. H. Hardin_, Sep 20 2010