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 A225050 #16 May 12 2014 13:16:20
%S A225050 1,4,24,148,920,5754,36204,229128,1458072,9325030,59905274,386368008,
%T A225050 2500651244,16234450288,105680341560,689579733648,4509096746904,
%U A225050 29539804567230,193843622021910,1273932593379600,8383551165082170,55238332546851630,364364231864557080
%N A225050 Number of shortest paths from one vertex of a cube (side = n units) to farthest vertex, along the grid on 3 surfaces meeting at another vertex.
%F A225050 a(n) = 2*binomial(3n,n) - binomial(2n,n).
%p A225050 A225050:=n->2*binomial(3*n,n)-binomial(2*n,n); seq(A225050(n), n=0..30); # _Wesley Ivan Hurt_, May 10 2014
%t A225050 Table[2*Binomial[3 n, n] - Binomial[2 n, n], {n, 30}]
%o A225050 (PARI) a(n)=2*binomial(3*n,n)-binomial(2*n,n) \\ _Charles R Greathouse IV_, Apr 26 2013
%Y A225050 Cf. A060774.
%K A225050 nonn,easy
%O A225050 0,2
%A A225050 _Ravichandran Subramanian_, Apr 25 2013