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 A237385 #7 Jul 23 2025 10:08:33 %S A237385 81,434,2336,12624,68064,366568,1976940,10657560,57441532,309578264, %T A237385 1668794652,8995139000,48484851148,261335232440,1408647749404, %U A237385 7592807398296,40926289471308,220597727495896,1189054017281884 %N A237385 Number of (n+1)X(1+1) 0..2 arrays colored with the maximum plus the upper median minus the minimum of every 2X2 subblock. %C A237385 Column 1 of A237391 %H A237385 R. H. Hardin, <a href="/A237385/b237385.txt">Table of n, a(n) for n = 1..210</a> %F A237385 Empirical: a(n) = 30*a(n-3) +349*a(n-4) +818*a(n-5) +3504*a(n-6) +7320*a(n-7) +9876*a(n-8) +18056*a(n-9) -14960*a(n-10) -63872*a(n-11) -133008*a(n-12) -307168*a(n-13) -194624*a(n-14) +71296*a(n-15) +344832*a(n-16) +1077248*a(n-17) +985088*a(n-18) -16384*a(n-19) -212992*a(n-20) %e A237385 Some solutions for n=5 %e A237385 ..2..1....1..1....1..1....0..2....2..1....2..2....2..0....2..0....1..1....0..1 %e A237385 ..0..0....2..1....1..1....2..1....2..0....1..2....2..1....0..0....2..0....2..1 %e A237385 ..0..2....0..0....2..2....1..2....1..1....1..1....0..0....0..0....0..2....0..2 %e A237385 ..0..2....0..2....1..0....1..1....1..0....0..2....1..1....0..2....1..1....0..0 %e A237385 ..0..0....1..2....0..1....2..0....2..2....0..0....2..0....0..2....1..1....1..0 %e A237385 ..0..1....0..1....2..2....2..1....1..1....1..2....2..2....1..0....0..1....1..2 %K A237385 nonn %O A237385 1,1 %A A237385 _R. H. Hardin_, Feb 07 2014