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 A218175 #6 Jul 22 2025 23:49:01 %S A218175 4,28,192,956,5494,30888,172038,964828,5400158,30225794,169223054, %T A218175 947302656,5303071898,29687164126,166191023656,930351759572, %U A218175 5208189255764,29155886563482,163217149535782,913703559802622 %N A218175 Number of nX2 arrays of the minimum value of corresponding elements and their horizontal and vertical neighbors in a random 0..3 nX2 array. %C A218175 Column 2 of A218181 %H A218175 R. H. Hardin, <a href="/A218175/b218175.txt">Table of n, a(n) for n = 1..210</a> %F A218175 Empirical: a(n) = 4*a(n-1) +8*a(n-2) +13*a(n-3) -33*a(n-4) -36*a(n-5) -86*a(n-6) -145*a(n-7) -161*a(n-8) +132*a(n-9) +538*a(n-10) +364*a(n-11) -112*a(n-12) -32*a(n-13) %e A218175 Some solutions for n=3 %e A218175 ..0..0....1..3....2..2....0..0....2..2....2..2....2..2....2..3....2..1....0..0 %e A218175 ..0..0....1..1....2..2....1..0....0..3....0..0....3..0....0..1....0..0....0..0 %e A218175 ..3..0....1..3....2..3....1..1....0..0....0..0....0..0....0..0....0..0....1..1 %K A218175 nonn %O A218175 1,1 %A A218175 _R. H. Hardin_ Oct 22 2012