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 A207416 #7 Jul 22 2025 20:23:29 %S A207416 14,196,720,2760,13260,50139,175903,656508,2338562,7964440,27387966, %T A207416 93272992,311246157,1035796645,3435764764,11296068814,36992161254, %U A207416 120875903016,393346541394,1276189913811,4133174774211,13356263152094 %N A207416 Number of nX5 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically. %C A207416 Column 5 of A207419 %H A207416 R. H. Hardin, <a href="/A207416/b207416.txt">Table of n, a(n) for n = 1..210</a> %F A207416 Empirical: a(n) = 7*a(n-1) -18*a(n-2) +72*a(n-3) -303*a(n-4) +553*a(n-5) -1440*a(n-6) +4899*a(n-7) -5932*a(n-8) +12977*a(n-9) -41708*a(n-10) +25293*a(n-11) -68030*a(n-12) +222709*a(n-13) +1292*a(n-14) +276787*a(n-15) -815366*a(n-16) -465935*a(n-17) -1032664*a(n-18) +2055611*a(n-19) +2236058*a(n-20) +3161899*a(n-21) -3425378*a(n-22) -5665821*a(n-23) -6993506*a(n-24) +3611199*a(n-25) +8921806*a(n-26) +10534143*a(n-27) -2236191*a(n-28) -9255318*a(n-29) -10408700*a(n-30) +805371*a(n-31) +6396787*a(n-32) +6551264*a(n-33) -463326*a(n-34) -2910858*a(n-35) -2406262*a(n-36) +433824*a(n-37) +836762*a(n-38) +458312*a(n-39) -259060*a(n-40) -136464*a(n-41) -21136*a(n-42) +62656*a(n-43) +10816*a(n-44) -7680*a(n-46) %e A207416 Some solutions for n=4 %e A207416 ..0..0..0..0..0....1..0..1..1..1....1..0..1..1..1....0..1..1..0..1 %e A207416 ..1..0..0..0..0....0..1..1..1..0....0..1..1..1..1....1..1..1..0..0 %e A207416 ..0..1..1..1..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0 %e A207416 ..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0 %K A207416 nonn %O A207416 1,1 %A A207416 _R. H. Hardin_ Feb 17 2012