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 A207498 #7 Jul 22 2025 20:30:26 %S A207498 18,324,1526,7305,41938,237576,1413961,8384076,50497372,304338351, %T A207498 1845174892,11203596798,68215344617,415886615986,2539409090804, %U A207498 15520995658437,94955670400794,581344596875918,3561439696930289 %N A207498 Number of nX6 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically. %C A207498 Column 6 of A207500 %H A207498 R. H. Hardin, <a href="/A207498/b207498.txt">Table of n, a(n) for n = 1..210</a> %F A207498 Empirical: a(n) = 14*a(n-1) +29*a(n-2) -1135*a(n-3) +1334*a(n-4) +41801*a(n-5) -95619*a(n-6) -930468*a(n-7) +2649845*a(n-8) +14061339*a(n-9) -44531949*a(n-10) -153782559*a(n-11) +513955813*a(n-12) +1268284717*a(n-13) -4323228199*a(n-14) -8122717309*a(n-15) +27453042595*a(n-16) +41304642649*a(n-17) -134693996321*a(n-18) -169631226639*a(n-19) +518946014345*a(n-20) +569790977071*a(n-21) -1588299569143*a(n-22) -1578940833367*a(n-23) +3893050518502*a(n-24) +3627356972069*a(n-25) -7681599053950*a(n-26) -6920685329456*a(n-27) +12232494417499*a(n-28) +10957506877510*a(n-29) -15717504128604*a(n-30) -14358725835477*a(n-31) +16239508261914*a(n-32) +15507242940206*a(n-33) -13389245012700*a(n-34) -13725161001954*a(n-35) +8684851178462*a(n-36) +9883191760144*a(n-37) -4316851021696*a(n-38) -5735269358684*a(n-39) +1556717902748*a(n-40) +2648505812720*a(n-41) -349241905640*a(n-42) -956522388168*a(n-43) +12400217520*a(n-44) +263523136512*a(n-45) +23917848240*a(n-46) -53319501440*a(n-47) -9924197504*a(n-48) +7432734624*a(n-49) +2117787456*a(n-50) -626758464*a(n-51) -264414848*a(n-52) +20661120*a(n-53) +17834496*a(n-54) +817920*a(n-55) -474624*a(n-56) -55296*a(n-57) for n>58 %e A207498 Some solutions for n=4 %e A207498 ..0..0..1..0..0..1....1..0..1..0..1..0....0..1..0..1..0..0....0..1..0..1..0..0 %e A207498 ..0..0..1..0..0..1....0..1..0..0..1..0....1..0..1..0..1..0....1..1..1..1..1..1 %e A207498 ..0..0..1..0..0..1....1..1..1..0..1..0....1..1..0..1..0..0....0..0..1..0..0..1 %e A207498 ..0..0..1..0..0..1....1..0..1..0..1..0....1..1..1..1..1..0....1..1..1..1..1..0 %K A207498 nonn %O A207498 1,1 %A A207498 _R. H. Hardin_ Feb 18 2012