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 A232318 #8 Jul 23 2025 07:18:27 %S A232318 5,24,139,853,5241,32089,196698,1205422,7387476,45274221,277463582, %T A232318 1700438900,10421159854,63866201729,391404773682,2398728792093, %U A232318 14700637816523,90093032996396,552136219923131,3383773364176424 %N A232318 Number of (2+1)X(n+1) 0..1 arrays with every element equal to some horizontal or antidiagonal neighbor, with top left element zero. %C A232318 Row 2 of A232316 %H A232318 R. H. Hardin, <a href="/A232318/b232318.txt">Table of n, a(n) for n = 1..210</a> %F A232318 Empirical: a(n) = 5*a(n-1) +9*a(n-2) -10*a(n-3) -19*a(n-4) +9*a(n-5) +21*a(n-6) -15*a(n-8) -5*a(n-9) +5*a(n-10) +4*a(n-11) -2*a(n-12) for n>14 %e A232318 Some solutions for n=7 %e A232318 ..0..0..1..0..1..0..0..1....0..0..0..0..0..1..0..0....0..0..0..0..1..1..1..0 %e A232318 ..0..1..0..1..1..0..1..0....0..0..1..1..1..1..1..0....0..1..1..1..0..1..0..0 %e A232318 ..0..0..1..1..1..1..0..0....1..1..0..0..1..1..0..0....1..0..0..0..1..1..1..1 %K A232318 nonn %O A232318 1,1 %A A232318 _R. H. Hardin_, Nov 22 2013