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 A223879 #6 Jul 23 2025 04:37:49 %S A223879 1024,1048576,152918517,5941888105,122550633425,1705349067795, %T A223879 18196418303111,160679898741339,1229765413154086,8391601872683197, %U A223879 51974570843642850,295702768916620339,1558622615940769358 %N A223879 Number of 5Xn 0..3 arrays with rows, diagonals and antidiagonals unimodal. %C A223879 Row 5 of A223876 %H A223879 R. H. Hardin, <a href="/A223879/b223879.txt">Table of n, a(n) for n = 1..30</a> %e A223879 Some solutions for n=3 %e A223879 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0 %e A223879 ..0..2..0....0..0..2....0..2..2....0..2..2....0..0..0....0..2..0....0..0..0 %e A223879 ..1..2..1....2..2..2....0..0..0....0..2..2....2..0..0....3..0..0....2..2..1 %e A223879 ..0..1..0....0..2..3....0..0..2....2..2..1....0..3..2....3..2..2....1..3..0 %e A223879 ..0..2..1....3..3..3....1..1..1....1..2..0....1..3..0....0..3..2....0..1..2 %K A223879 nonn %O A223879 1,1 %A A223879 _R. H. Hardin_ Mar 28 2013