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 A185771 #10 Jan 08 2015 16:37:17 %S A185771 81,558,3844,26784,186624,1296000,9000000,62568000,434972736, %T A185771 3022785216,21006444096,146001569472,1014758051904,7052535822528, %U A185771 49014897132096,340658500222656,2367611084874816,16455017381102784,114363207176279616 %N A185771 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock sum equal to any horizontal or vertical neighbor 2 X 2 subblock sum. %C A185771 Column 1 of A185777. %H A185771 R. H. Hardin, <a href="/A185771/b185771.txt">Table of n, a(n) for n = 1..200</a> %F A185771 Empirical: a(n)= 3*a(n-1) +96*a(n-3) +504*a(n-4) +792*a(n-5) +2304*a(n-6) -13824*a(n-8) -13824*a(n-9). %F A185771 Empirical: G.f.: -x*(-81 -315*x -2170*x^2 -7476*x^3 -11880*x^4 -21720*x^5 +25200*x^6 +177120*x^7 +155520*x^8) / ( (24*x^3+24*x^2+3*x-1) *(576*x^6-72*x^4-24*x^2-1) ). - _R. J. Mathar_, Jan 08 2015 %e A185771 Some solutions for 3 X 2: %e A185771 ..2..1....0..2....2..1....2..1....0..1....0..2....1..2....0..0....2..1....0..1 %e A185771 ..0..2....2..2....0..1....1..1....2..1....1..0....2..0....2..1....0..2....0..2 %e A185771 ..0..0....0..0....1..0....0..2....2..0....2..2....1..1....1..1....1..1....2..2 %K A185771 nonn %O A185771 1,1 %A A185771 _R. H. Hardin_ Feb 03 2011