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 A207178 #7 Jul 22 2025 20:04:55 %S A207178 13,169,1393,11227,95299,816667,6951227,59040685,501829587,4267306637, %T A207178 36285226037,308510297123,2623052584859,22302344594307, %U A207178 189625018122875,1612277620195105,13708297950194541,116554044545138583 %N A207178 Number of nX4 0..1 arrays avoiding 0 0 0 horizontally and 0 1 0 vertically. %C A207178 Column 4 of A207182 %H A207178 R. H. Hardin, <a href="/A207178/b207178.txt">Table of n, a(n) for n = 1..210</a> %F A207178 Empirical: a(n) = 8*a(n-1) -14*a(n-2) +122*a(n-3) +241*a(n-4) +205*a(n-5) +1610*a(n-6) -1293*a(n-7) -8293*a(n-8) -3968*a(n-9) +3959*a(n-10) +8030*a(n-11) +12180*a(n-12) +3570*a(n-13) -245*a(n-14) -2586*a(n-15) -2664*a(n-16) -336*a(n-17) -215*a(n-18) +31*a(n-19) +36*a(n-20) -5*a(n-21) -a(n-22) -2*a(n-23) -a(n-24) %e A207178 Some solutions for n=4 %e A207178 ..0..1..1..0....1..1..0..1....1..1..0..1....0..0..1..0....1..0..0..1 %e A207178 ..0..0..1..0....1..0..1..1....1..1..0..1....0..0..1..0....0..1..1..0 %e A207178 ..0..0..1..1....0..0..1..1....0..1..1..0....1..1..0..0....1..1..1..1 %e A207178 ..1..0..0..1....0..0..1..1....0..0..1..1....1..1..0..0....1..0..1..1 %K A207178 nonn %O A207178 1,1 %A A207178 _R. H. Hardin_ Feb 15 2012