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 A208174 #7 Jul 22 2025 21:13:51 %S A208174 715,7594479,84091222866,931104734002155,10309684155118737894, %T A208174 114154269785454920027391,1263976383376771173195964686, %U A208174 13995414281804368959953485044237,154964620775524737157861783733965485 %N A208174 Number of nX7 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors. %C A208174 Column 7 of A208175 %H A208174 R. H. Hardin, <a href="/A208174/b208174.txt">Table of n, a(n) for n = 1..210</a> %e A208174 Some solutions for n=4 %e A208174 ..0..1..1..2..0..1..0....0..1..0..0..1..0..0....0..0..0..0..0..0..0 %e A208174 ..0..0..0..3..0..1..1....2..1..1..0..0..3..1....0..1..1..0..1..0..1 %e A208174 ..2..0..2..2..1..0..3....3..0..1..0..1..3..2....1..0..0..2..1..2..3 %e A208174 ..2..2..0..2..3..3..0....3..1..3..2..2..1..1....3..0..3..2..2..0..1 %K A208174 nonn %O A208174 1,1 %A A208174 _R. H. Hardin_ Feb 24 2012