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 A185471 #7 Jul 22 2025 09:48:04 %S A185471 13659,76309,308692,1043186,3097348,8297059,20411234,46732687, %T A185471 100636591,205574323,401123377,751921908,1360579387,2385984676, %U A185471 4068843506,6766785098,11002001311,17525142877,27400120766,42115574722,63730107482 %N A185471 Number of (n+2)X5 0..2 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order. %C A185471 Column 3 of A185477 %H A185471 R. H. Hardin, <a href="/A185471/b185471.txt">Table of n, a(n) for n = 1..200</a> %F A185471 Empirical: a(n) = (1/444787200)*n^13 %F A185471 + (107/479001600)*n^12 %F A185471 + (11/1088640)*n^11 %F A185471 + (3623/6220800)*n^10 %F A185471 + (78227/3628800)*n^9 %F A185471 + (6420917/14515200)*n^8 %F A185471 + (148481/27216)*n^7 %F A185471 + (1861160843/43545600)*n^6 %F A185471 + (4966108109/21772800)*n^5 %F A185471 + (1448539279/1555200)*n^4 %F A185471 + (3663351401/1330560)*n^3 %F A185471 + (2013261953/415800)*n^2 %F A185471 + (15650889/3640)*n %F A185471 + 556 %e A185471 Some solutions for 4X5 %e A185471 ..0..0..0..1..2....0..0..0..0..0....0..0..0..0..2....0..0..0..1..1 %e A185471 ..0..0..1..1..2....0..0..1..2..2....0..0..0..2..2....0..0..0..1..2 %e A185471 ..0..1..1..2..0....1..1..2..1..1....0..0..1..0..1....0..1..1..1..2 %e A185471 ..2..1..2..0..2....2..2..2..1..2....1..2..2..1..1....1..1..2..2..2 %K A185471 nonn %O A185471 1,1 %A A185471 _R. H. Hardin_ Jan 28 2011