# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a221737 Showing 1-1 of 1 %I A221737 #8 Aug 10 2018 17:33:47 %S A221737 1,17,152,1347,11917,105408,932331,8246429,72939328,645145427, %T A221737 5706285509,50471867376,446421650827,3948581668413,34925047119456, %U A221737 308910646572419,2732302328399893,24167104943016272,213757077778269179 %N A221737 Number of 2 X n arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out left turns. %C A221737 Row 2 of A221736. %H A221737 R. H. Hardin, Table of n, a(n) for n = 1..210 %F A221737 Empirical: a(n) = 15*a(n-1) - 67*a(n-2) + 120*a(n-3) - 80*a(n-4) + 10*a(n-5) for n>6. %F A221737 Empirical g.f.: x*(1 + 2*x - 36*x^2 + 86*x^3 - 64*x^4 + 12*x^5) / (1 - 15*x + 67*x^2 - 120*x^3 + 80*x^4 - 10*x^5). - _Colin Barker_, Aug 10 2018 %e A221737 Some solutions for n=3: %e A221737 ..0..3..0....2..0..1....1..0..1....1..2..0....1..0..1....0..2..1....0..3..0 %e A221737 ..1..1..1....1..2..0....1..3..0....0..2..1....2..2..0....0..3..0....2..1..0 %Y A221737 Cf. A221736. %K A221737 nonn %O A221737 1,2 %A A221737 _R. H. Hardin_, Jan 22 2013 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE