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 A230063 #8 Jun 02 2025 08:40:35 %S A230063 0,9,45,441,3645,31329,266805,2277081,19424205,165714129,1413721125, %T A230063 12060652041,102890947005,877775988609,7488419962005,63884675998521, %U A230063 545008403548845,4649536929125169,39665798745571845,338394040998364521 %N A230063 Number of nX3 0..2 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j). %C A230063 Column 3 of A230068 %H A230063 R. H. Hardin, <a href="/A230063/b230063.txt">Table of n, a(n) for n = 1..210</a> %F A230063 Empirical: a(n) = 7*a(n-1) +14*a(n-2) -8*a(n-3). %F A230063 Empirical: G.f.: -9*x^2*(-1+2*x) / ( (2*x+1)*(4*x^2-9*x+1) ). - _R. J. Mathar_, Mar 21 2016 %e A230063 Some solutions for n=4 %e A230063 ..0..1..0....2..0..2....1..2..1....0..2..0....0..1..0....0..0..0....0..2..0 %e A230063 ..1..2..0....2..0..2....0..1..0....2..2..0....1..2..1....2..2..2....0..2..0 %e A230063 ..0..2..1....2..2..2....0..1..0....0..0..0....1..2..0....1..2..0....2..2..0 %e A230063 ..0..1..0....0..0..0....1..2..1....2..2..2....0..1..0....0..1..0....0..0..0 %K A230063 nonn %O A230063 1,2 %A A230063 _R. H. Hardin_, Oct 08 2013