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 A194605 #16 Mar 19 2023 08:21:38 %S A194605 0,0,0,2080,27768,181032,807040,2817240,8271480,21328048,49692672, %T A194605 106717680,214322680,406928280,736614528,1279735912,2145244920, %U A194605 3484996320,5506324480,8487206208,12794341752,18904506760,27429548160,39145417080,55025652088,76279746192 %N A194605 Number of ways to place 2 nonattacking kings on an n X n X n X n raumschach board (four-dimensional chessboard). %H A194605 Vincenzo Librandi, <a href="/A194605/b194605.txt">Table of n, a(n) for n = 0..10000</a> %H A194605 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (9,-36,84,-126,126,-84,36,-9,1). %F A194605 a(n) = (n^8 - (3*n-2)^4) / 2 for n>0. %F A194605 G.f.: 8*x^3*(260+1131*x+750*x^2+335*x^3+75*x^4-30*x^5-x^6)/(1-x)^9. - _Bruno Berselli_, Aug 31 2011 %Y A194605 Cf. A061995, A166540. %Y A194605 Cf. A194604 for the general d-dimensional case. %K A194605 nonn,easy %O A194605 0,4 %A A194605 _Andrew Woods_, Aug 30 2011