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 A100437 #12 Apr 07 2017 10:40:05
%S A100437 1,5,15,25,55,75,140,175,225,275,448,504,770,882,1022,1134,1626,1782,
%T A100437 2460,2670,2970,3270,4345,4565,5135,5585,6100,6505,8338,8679,10927,
%U A100437 11525,12393,13261,14345,14787,18187,19344,20618,21346,25823,26698
%N A100437 Number of distinct products i*j*k*l for 1 <= i <= j <= k <= l <= n.
%H A100437 Seiichi Manyama, <a href="/A100437/b100437.txt">Table of n, a(n) for n = 1..200</a>
%p A100437 f:=proc(n) local i,j,k,l,t1; t1:={}; for i from 1 to n do for j from i to n do for k from j to n do for l from k to n do t1:={op(t1),i*j*k*l}; od: od: od: od: t1:=convert(t1,list); nops(t1); end;
%t A100437 f[n_] := Length[ Union[ Flatten[ Table[ i*j*k*l, {i, n}, {j, i, n}, {k, j, n}, {l, k, n}] ]]]; Table[ f[n], {n, 45}] (* _Robert G. Wilson v_, Dec 14 2004 *)
%o A100437 (PARI) pr(n)=my(v=List());for(i=1,n, for(j=i,n, listput(v, i*j))); Set(v)
%o A100437 a(n)=my(u=List(),v=pr(n)); for(i=1,#v,for(j=i,#v,listput(u,v[i]*v[j]))); #Set(u) \\ _Charles R Greathouse IV_, Mar 04 2014
%Y A100437 Cf. A027425, A027430, A100435, A100436, A100438.
%K A100437 nonn
%O A100437 1,2
%A A100437 _N. J. A. Sloane_, Nov 21 2004
%E A100437 More terms from _Robert G. Wilson v_, Dec 14 2004