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 A246623 #3 Aug 31 2014 14:11:24 %S A246623 1,1,14,9918,964948464,25071989721176760,284751719071722748492598160, %T A246623 2093930745462011336917616846237237197680, %U A246623 13828562491398961948219629077212979214965847920914986240,108581107327233631269616107897051314148463756259194308769323017769436778880 %N A246623 Number of paths of a chess rook in an n-dimensional hypercube from (0...0) to (n...n) where the rook may move in steps that are multiples of (1,0..0), (0,1,0..0), ..., (0..0,1). %Y A246623 Main diagonal of A181731. %K A246623 nonn %O A246623 0,3 %A A246623 _Alois P. Heinz_, Aug 31 2014