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 A214590 #12 Aug 21 2025 10:02:07 %S A214590 4,8,62,1862,187862,63120962,71200442882,272199293130242, %T A214590 3552472974642762242,159161446682919676638722, %U A214590 24593308418551382594861736962,13156534644821921838477614251069442 %N A214590 Number of nXnXn triangular 0..3 arrays with every horizontal row having the same average value. %C A214590 Column 3 of A214595. %C A214590 a(n) appears to equal 2*A386650(n) + 2 for n >= 1, where A386650(n) = product of first n quadrinomial coefficients (A005725). - _Paul D. Hanna_, Aug 20 2025 %H A214590 R. H. Hardin, <a href="/A214590/b214590.txt">Table of n, a(n) for n = 1..61</a> %e A214590 Some solutions for n=4 %e A214590 .....2........2........2........2........2........1........2........2 %e A214590 ....1.3......1.3......3.1......2.2......3.1......0.2......3.1......2.2 %e A214590 ...1.3.2....3.2.1....2.3.1....3.0.3....0.3.3....1.0.2....2.3.1....3.0.3 %e A214590 ..1.2.2.3..3.0.3.2..3.2.3.0..0.3.3.2..3.2.1.2..0.0.3.1..3.0.3.2..3.2.0.3 %Y A214590 Cf. A214595, A386650. %K A214590 nonn,changed %O A214590 1,1 %A A214590 _R. H. Hardin_, Jul 22 2012