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 A065420 #10 Sep 02 2018 15:02:14
%S A065420 2,6,6,12,30,12,20,90,90,20,30,210,380,210,30,42,420,1190,1190,420,42,
%T A065420 56,756,3080,4830,3080,756,56,72,1260,6972,15750,15750,6972,1260,72,
%U A065420 90,1980,14280,43890,63252,43890,14280,1980,90,110,2970,27060,108570,212982
%N A065420 Triangle T(n,k) = binomial(n+2,k+1)*(binomial(n+2,k+1)-1), n >=0, 0 <= k <= n.
%C A065420 T(n,k) = T(n,n-k). - _Robert Israel_, Jan 08 2017
%H A065420 Robert Israel, <a href="/A065420/b065420.txt">Table of n, a(n) for n = 0..10010</a> (rows 0 to 140, flattened)
%F A065420 From _Robert Israel_, Jan 08 2017: (Start)
%F A065420 T(n,0) = (n+1)*(n+2) = A002378(n+1).
%F A065420 T(n,1) = n*(n+1)*(n+2)*(n+3)/4 = A033487(n). (End)
%e A065420 2; 6,6; 12,30,12; 20,90,90,20; ...
%p A065420 T:= (n,k) -> binomial(n+2,k+1)*(binomial(n+2,k+1)-1):
%p A065420 seq(seq(T(n,k),k=0..n),n=0..10); # _Robert Israel_, Jan 08 2017
%t A065420 #(#-1)&/@Table[Binomial[n+2,k+1],{n,0,10},{k,0,n}]//Flatten (* _Harvey P. Dale_, Sep 02 2018 *)
%Y A065420 Cf. A002378, A033487.
%K A065420 nonn,easy,tabl
%O A065420 0,1
%A A065420 Gary W. Adamson, Nov 15 2001
%E A065420 More terms from _Naohiro Nomoto_, Nov 22 2001