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 A207950 #7 Jun 26 2022 12:58:36 %S A207950 10,100,370,1369,3478,8836,18330,38025,69420,126736,211820,354025, %T A207950 554540,868624,1294548,1929321,2764110,3960100,5494390,7623121, %U A207950 10298530,13912900,18377710,24275329,31453968,40755456,51933840,66178225,83107160 %N A207950 Number of 4 X n 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 1 0 and 1 0 1 vertically. %C A207950 Row 4 of A207949. %H A207950 R. H. Hardin, <a href="/A207950/b207950.txt">Table of n, a(n) for n = 1..210</a> %F A207950 Empirical: a(n) = 2*a(n-1) +6*a(n-2) -14*a(n-3) -14*a(n-4) +42*a(n-5) +14*a(n-6) -70*a(n-7) +70*a(n-9) -14*a(n-10) -42*a(n-11) +14*a(n-12) +14*a(n-13) -6*a(n-14) -2*a(n-15) +a(n-16). %e A207950 Some solutions for n=4 %e A207950 ..0..0..0..0....0..1..0..1....1..0..0..0....1..0..0..0....1..1..1..1 %e A207950 ..1..1..1..0....0..1..0..1....1..0..0..0....0..1..0..0....1..1..1..1 %e A207950 ..1..1..1..0....1..0..1..0....1..1..1..0....0..1..0..1....1..1..1..1 %e A207950 ..1..1..0..1....1..0..1..0....1..1..1..1....1..1..1..1....1..1..1..0 %Y A207950 Cf. A207949. %K A207950 nonn %O A207950 1,1 %A A207950 _R. H. Hardin_, Feb 21 2012