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 A359805 #16 Jun 16 2023 05:31:50
%S A359805 3,6,5,9,8,12,15,20,7,10,18,21,16,24,12,15,27,9,30,40,33,24,28,14,20,
%T A359805 36,39,48,33,42,11,25,32,45,16,60,48,51,24,21,30,54,65,40,57,36,18,39,
%U A359805 60,13,35,63,80,66,48,56,60,69,28,40,72,20,75,78,36,56,88,100
%N A359805 Irregular triangle T(n, k), n > 0, k = 1..A056137(A009023(n)), read by rows: the n-th row contains the numbers m < A009023(n) such that A009023(n)^2 + m^2 is a square.
%C A359805 See A360020 for the corresponding hypotenuses.
%H A359805 Rémy Sigrist, <a href="/A359805/b359805.txt">Table of n, a(n) for n = 1..10011</a>
%H A359805 <a href="/index/Ps#PyTrip">Index entries related to Pythagorean Triples</a>
%e A359805 Triangle T(n, k) begins:
%e A359805 n A009023(n) n-th row
%e A359805 -- ---------- ---------
%e A359805 1 4 3
%e A359805 2 8 6
%e A359805 3 12 5, 9
%e A359805 4 15 8
%e A359805 5 16 12
%e A359805 6 20 15
%e A359805 7 21 20
%e A359805 8 24 7, 10, 18
%e A359805 9 28 21
%e A359805 10 30 16
%e A359805 11 32 24
%e A359805 12 35 12
%e A359805 13 36 15, 27
%e A359805 14 40 9, 30
%o A359805 (PARI) { for (n=1, 105, for (m=1, n-1, if (issquare(n^2+m^2), print1 (m", ")))) }
%Y A359805 Cf. A009023, A056137, A360020.
%K A359805 nonn,look,tabf
%O A359805 1,1
%A A359805 _Rémy Sigrist_, Mar 08 2023