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 A214589 #13 Aug 21 2025 10:02:02 %S A214589 3,5,23,401,20351,2869211,1127599139,1248252244661,3918263795984603, %T A214589 35080215765450132755,899912775031092255512711, %U A214589 66403663756769266442027284403,14140062564030204365431731967633343 %N A214589 Number of nXnXn triangular 0..2 arrays with every horizontal row having the same average value. %C A214589 Column 2 of A214595. %C A214589 a(n) appears to equal A386649(n) + 2 for n >= 1, where A386649(n) = product of first n central trinomial coefficients (A002426). - _Paul D. Hanna_, Aug 20 2025 %H A214589 R. H. Hardin, <a href="/A214589/b214589.txt">Table of n, a(n) for n = 1..66</a> %e A214589 Some solutions for n=4 %e A214589 .....1........1........1........1........1........1........1........1 %e A214589 ....1.1......2.0......0.2......0.2......0.2......2.0......0.2......1.1 %e A214589 ...2.0.1....2.0.1....1.2.0....2.1.0....1.1.1....2.1.0....1.2.0....0.2.1 %e A214589 ..0.2.1.1..1.0.1.2..0.2.2.0..1.2.0.1..2.1.1.0..0.1.1.2..0.2.1.1..0.0.2.2 %Y A214589 Cf. A214595, A386649. %K A214589 nonn,changed %O A214589 1,1 %A A214589 _R. H. Hardin_, Jul 22 2012