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 A380749 #24 Mar 02 2025 23:40:36
%S A380749 0,374,450,375,301,478,228,359,238,515,206,879,259,506,780,349,284,
%T A380749 762,135,916,905,493,99,1189,423,306,318,869,70,1879,97,311,714,250,
%U A380749 778,1300,109,258,483,1334,71,1987,93,545,1451,303,64,1156,202,504,481,822,71
%N A380749 a(n) is the number of positive integer solutions of n*x*y*z*w = (x + n) * (y + n) * (z + n) * (w + n), x <= y <= z <= w.
%H A380749 Zhining Yang, <a href="/A380749/b380749.txt">Table of n, a(n) for n = 1..2130</a>
%e A380749 For n=5, a(5) = 301 because 5*x*y*z*w = (x + 5)*(y + 5)*(z + 5)*(w + 5), 0 < x <= y <= z <= w has 301 positive integer solutions: {{2,12,596,357595}, {2,12,597,179095}, {2,12,598,119595}, ..., {6,7,9,220}, {6,10,11,20}, {7,9,10,20}}.
%t A380749 Table[Length@Solve[n*x*y*z*w == (x + n) (y + n) (z + n) (w + n) &&
%t A380749 0 < x <= y <= z <= w, {x, y, z, w}, Integers], {n, 10}]
%Y A380749 Cf. A374059, A375787, A380750.
%K A380749 nonn
%O A380749 1,2
%A A380749 _Zhining Yang_, Jan 31 2025