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 A189697 #7 Jul 22 2025 11:53:28 %S A189697 12,144,1298,11637,107720,997264,9205575,84987637,784968276, %T A189697 7250191247,66962229085,618461917882,5712150826447,52757783396467, %U A189697 487273980078400,4500491954718670,41566823940472846,383913783539151670 %N A189697 Number of 4Xn binary arrays without the pattern 0 0 1 diagonally, vertically or antidiagonally. %C A189697 Row 4 of A189696 %H A189697 R. H. Hardin, <a href="/A189697/b189697.txt">Table of n, a(n) for n = 1..200</a> %F A189697 Empirical: a(n) = 12*a(n-1) -14*a(n-2) -138*a(n-3) +487*a(n-4) -2320*a(n-5) +3108*a(n-6) +19078*a(n-7) -43985*a(n-8) +63715*a(n-9) -58934*a(n-10) -538144*a(n-11) +884140*a(n-12) +235100*a(n-13) -383512*a(n-14) +2515360*a(n-15) -4168592*a(n-16) -2271152*a(n-17) +2599872*a(n-18) -3563680*a(n-19) +6711296*a(n-20) +3621888*a(n-21) -3288064*a(n-22) +1212416*a(n-23) -3323392*a(n-24) -1750016*a(n-25) +1122304*a(n-26) +45056*a(n-27) +393216*a(n-28) +196608*a(n-29) %e A189697 Some solutions for 4X3 %e A189697 ..1..1..0....1..1..0....1..0..1....1..0..1....0..1..0....1..1..1....0..1..0 %e A189697 ..1..1..1....0..1..0....1..1..0....1..1..1....1..1..0....0..1..0....0..0..1 %e A189697 ..1..1..1....0..0..0....0..0..1....0..0..1....0..1..0....1..1..1....0..1..0 %e A189697 ..0..0..0....0..1..0....0..1..1....0..1..0....1..0..0....0..1..0....0..1..0 %K A189697 nonn %O A189697 1,1 %A A189697 _R. H. Hardin_ Apr 25 2011