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 A208373 #7 Jul 22 2025 21:18:33 %S A208373 31,961,11067,177909,2563359,38542393,570085195,8487780687, %T A208373 126039261499,1873614472027,27839846618695,413742327695195, %U A208373 6148396146149603,91370604275750753,1357831649082497201,20178435819755002559 %N A208373 Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 0 1 0 vertically. %C A208373 Row 7 of A208369 %H A208373 R. H. Hardin, <a href="/A208373/b208373.txt">Table of n, a(n) for n = 1..210</a> %F A208373 Empirical: a(n) = 178*a(n-2) +932*a(n-3) -2956*a(n-4) -23754*a(n-5) +20253*a(n-6) +256486*a(n-7) -113835*a(n-8) -1502278*a(n-9) +783938*a(n-10) +4923968*a(n-11) -3657059*a(n-12) -8430388*a(n-13) +8233841*a(n-14) +6798200*a(n-15) -8443642*a(n-16) -2506050*a(n-17) +4235409*a(n-18) +420518*a(n-19) -1084169*a(n-20) -45082*a(n-21) +134907*a(n-22) +7426*a(n-23) -6196*a(n-24) -610*a(n-25) %e A208373 Some solutions for n=4 %e A208373 ..0..1..1..0....0..1..1..1....0..1..1..1....1..0..1..0....0..1..0..1 %e A208373 ..1..1..0..0....1..0..1..1....1..0..1..1....1..1..0..1....0..1..0..0 %e A208373 ..1..0..1..0....1..0..1..0....1..1..0..0....1..1..1..1....0..1..0..0 %e A208373 ..0..1..1..0....1..0..1..0....1..1..0..1....0..1..1..1....0..1..0..0 %e A208373 ..1..1..1..0....1..0..1..0....1..1..0..1....1..1..0..0....0..1..0..0 %e A208373 ..1..0..1..0....1..0..1..0....1..1..0..0....1..0..1..0....0..1..0..0 %e A208373 ..1..1..0..0....1..0..1..0....1..1..0..0....1..0..1..0....0..1..0..0 %K A208373 nonn %O A208373 1,1 %A A208373 _R. H. Hardin_ Feb 25 2012