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 A172229 #21 Feb 16 2025 08:33:11
%S A172229 0,2,22,84,215,442,792,1292,1969,2850,3962,5332,6987,8954,11260,13932,
%T A172229 16997,20482,24414,28820,33727,39162,45152,51724,58905,66722,75202,
%U A172229 84372,94259,104890,116292,128492,141517,155394,170150,185812,202407,219962,238504
%N A172229 Number of ways to place 3 nonattacking wazirs on a 3 X n board.
%C A172229 A wazir is a (fairy chess) leaper [0,1].
%H A172229 Vincenzo Librandi, <a href="/A172229/b172229.txt">Table of n, a(n) for n = 1..1000</a>
%H A172229 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens and kings on boards of various sizes</a>
%H A172229 R. J. Mathar, <a href="https://vixra.org/abs/2404.0122">Bivariate generating functions for non-attacking wazirs on rectangular boards</a>, viXra:2404.0122 (2024) Section 3.
%H A172229 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GridGraph.html">Grid Graph</a>
%H A172229 Wikipedia, <a href="https://en.wikipedia.org/wiki/Wazir_(chess)">Wazir (chess)</a>
%F A172229 a(n) = (3*n - 5)*(3*n^2 - 8*n + 8)/2, n>=2.
%F A172229 G.f.: x^2*(3*x^3+8*x^2+14*x+2)/(x-1)^4. - _Vaclav Kotesovec_, Mar 25 2010
%t A172229 CoefficientList[Series[x (3 x^3 + 8 x^2 + 14 x + 2) / (x - 1)^4, {x, 0, 50}], x] (* _Vincenzo Librandi_, May 28 2013 *)
%Y A172229 Cf. A172226, A061989.
%Y A172229 Column w=3 of A371967.
%K A172229 nonn,easy
%O A172229 1,2
%A A172229 _Vaclav Kotesovec_, Jan 29 2010