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 A207308 #7 Jul 22 2025 20:17:00 %S A207308 10,100,350,1271,3773,11497,36868,116117,361408,1134028,3564401, %T A207308 11172725,35022953,109875752,344642683,1080804698,3389755038, %U A207308 10631811817,33344912997,104580332523,328001505224,1028729270911,3226449372360 %N A207308 Number of 5Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 0 vertically. %C A207308 Row 5 of A207305 %H A207308 R. H. Hardin, <a href="/A207308/b207308.txt">Table of n, a(n) for n = 1..210</a> %F A207308 Empirical: a(n) = a(n-1) +2*a(n-2) +11*a(n-3) +13*a(n-4) +3*a(n-5) -12*a(n-6) -27*a(n-7) -13*a(n-8) -3*a(n-9) +15*a(n-10) +8*a(n-11) +4*a(n-12) -5*a(n-13) -a(n-14) -a(n-15) +2*a(n-16) -a(n-17) for n>18 %e A207308 Some solutions for n=4 %e A207308 ..0..1..0..0....1..0..0..1....1..1..1..1....1..0..0..1....1..0..0..1 %e A207308 ..1..1..1..1....1..1..1..0....1..0..0..1....0..0..1..1....1..0..0..1 %e A207308 ..0..1..1..1....1..0..0..1....1..1..1..1....0..0..1..1....1..0..0..1 %e A207308 ..1..1..1..1....1..1..0..0....1..0..0..1....0..0..1..1....1..0..0..1 %e A207308 ..1..1..1..1....1..0..0..1....1..0..0..1....0..0..1..1....1..0..0..1 %K A207308 nonn %O A207308 1,1 %A A207308 _R. H. Hardin_ Feb 16 2012