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 A214909 #6 Jul 22 2025 23:20:15 %S A214909 2,38,242,1802,7550,31412,100350,310079,811472,2065406,4695974, %T A214909 10458806,21370898,42897546,80938346,150245395,265231474,462690716, %U A214909 774729470,1283610082,2057355212,3266479406,5043183866,7727895633,11557992252 %N A214909 Number of 5X5X5 triangular 0..n arrays with every horizontal row nondecreasing and having the same average value. %C A214909 Row 5 of A214906 %H A214909 R. H. Hardin, <a href="/A214909/b214909.txt">Table of n, a(n) for n = 1..210</a> %e A214909 Some solutions for n=4 %e A214909 ......2..........2..........2..........2..........2..........2..........2 %e A214909 .....2.2........1.3........2.2........1.3........2.2........2.2........1.3 %e A214909 ....2.2.2......0.3.3......1.2.3......1.1.4......2.2.2......1.1.4......1.2.3 %e A214909 ...1.1.3.3....1.1.3.3....0.1.3.4....1.1.3.3....0.2.3.3....0.1.3.4....0.2.2.4 %e A214909 ..1.1.2.3.3..0.1.2.3.4..0.0.2.4.4..1.2.2.2.3..0.2.2.3.3..1.1.2.3.3..0.1.1.4.4 %K A214909 nonn %O A214909 1,1 %A A214909 _R. H. Hardin_ Jul 29 2012