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 A207962 #7 Jul 22 2025 21:03:56 %S A207962 9,81,297,989,3080,9994,32358,104176,335940,1083914,3495930,11275444, %T A207962 36368274,117303034,378351488,1220339904,3936101206,12695569864, %U A207962 40948497182,132075911156,425999751988,1374026441136,4431806698176 %N A207962 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 0 vertically. %C A207962 Row 4 of A207960 %H A207962 R. H. Hardin, <a href="/A207962/b207962.txt">Table of n, a(n) for n = 1..210</a> %F A207962 Empirical: a(n) = a(n-1) +3*a(n-2) +11*a(n-3) +11*a(n-4) -a(n-5) -20*a(n-6) -27*a(n-7) -5*a(n-8) +20*a(n-9) +13*a(n-10) -3*a(n-11) -4*a(n-12) for n>15 %e A207962 Some solutions for n=4 %e A207962 ..0..0..1..1....1..0..0..1....1..1..1..1....1..1..1..0....1..0..0..1 %e A207962 ..1..1..0..0....1..0..0..1....1..1..0..0....0..1..1..0....0..1..1..0 %e A207962 ..1..1..1..1....1..0..0..1....0..1..1..1....1..1..1..0....1..0..0..1 %e A207962 ..1..1..0..0....1..0..0..1....1..0..0..1....1..1..1..0....1..1..1..1 %K A207962 nonn %O A207962 1,1 %A A207962 _R. H. Hardin_ Feb 21 2012