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 A138779 #4 May 24 2015 12:59:22
%S A138779 1,5,15,35,70,126,2,210,16,330,72,495,240,715,660,1001,1584,3,1365,
%T A138779 3432,33,1820,6864,198,2380,12870,858,3060,22880,3003,3876,38896,9009,
%U A138779 4,4845,63648,24024,56,5985,100776,58344,420
%N A138779 Triangle read by rows: T(n,k)=k*binomial(n-2k,3k+1) (n>=6, 0<=k<=(n-1)/5).
%C A138779 Row n contains floor((n-1)/5) terms.
%C A138779 Row sums yield A137360.
%D A138779 D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.
%p A138779 T:=proc(n,k) options operator, arrow: k*binomial(n-2*k,3*k+1) end proc: for n from 6 to 23 do seq(T(n,k),k=1..(n-1)*1/5) end do; # yields sequence in triangular form
%t A138779 Select[Flatten[Table[k*Binomial[n-2k,3k+1],{n,6,30},{k,0,(n-1)/5}]], #>0&] (* _Harvey P. Dale_, May 24 2015 *)
%Y A138779 Cf. A137360.
%K A138779 nonn,tabf
%O A138779 6,2
%A A138779 _Emeric Deutsch_, May 10 2008