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 A104713 #14 Aug 08 2015 21:32:05 %S A104713 1,4,1,10,5,1,20,15,6,1,35,35,21,7,1,56,70,56,28,8,1,84,126,126,84,36, %T A104713 9,1,120,210,252,210,120,45,10,1,165,330,462,462,330,165,55,11,1,220, %U A104713 495,792,924,792,495,220,66,12,1,286,715,1287,1716 %N A104713 Triangle T(n,k) = binomial(n,k), read by rows, 3 <= k <=n . %F A104713 T(n,k) = A007318(n,k) for n>=3, 3<=k<=n. %F A104713 From _Peter Bala_, Jul 16 2013: (Start) %F A104713 The following remarks assume an offset of 0. %F A104713 Riordan array (1/(1 - x)^4, x/(1 - x)). %F A104713 O.g.f.: 1/(1 - t)^3*1/(1 - (1 + x)*t) = 1 + (4 + x)*t + (10 + 5*x + x^2)*t^2 + .... %F A104713 E.g.f.: (1/x*d/dt)^3 (exp(t)*(exp(x*t) - 1 - x*t - (x*t)^2/2!)) = 1 + (4 + x)*t + (10 + 5*x + x^2)*t^2/2! + .... %F A104713 The infinitesimal generator for this triangle has the sequence [4,5,6,...] on the main subdiagonal and 0's elsewhere. (End) %e A104713 First few rows of the triangle are: %e A104713 1; %e A104713 4, 1; %e A104713 10, 5, 1; %e A104713 20, 15, 6, 1; %e A104713 35, 35, 21, 7, 1; %e A104713 56, 70, 56, 28, 8, 1; %e A104713 ... %p A104713 A104713 := proc(n,k) %p A104713 binomial(n,k) ; %p A104713 end proc; %p A104713 seq(seq( A104713(n,k),k=3..n),n=3..16) ; # _R. J. Mathar_, Oct 29 2011 %Y A104713 Cf. A007318, A104712, A002662 (row sums). %K A104713 nonn,tabl,easy %O A104713 3,2 %A A104713 _Gary W. Adamson_, Mar 19 2005