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 A076696 #9 Sep 11 2023 11:46:05 %S A076696 1,2,8,3,7,21,4,5,6,30,9,10,12,15,18 %N A076696 Triangle read by rows: n-th row contains n numbers whose product is a square; all numbers in triangle are distinct. %C A076696 Second solution. Both solutions are smaller than A076031. %e A076696 1^2 4^2 21^2 60^2 540^2 = (1)(2 8)(3 7 21)(4 5 6 30)(9 10 12 15 18) %Y A076696 Cf. A076031, A076596. %K A076696 more,nonn,tabl,obsc %O A076696 1,2 %A A076696 _Donald S. McDonald_, Nov 10 2002 %E A076696 It is not clear to me how one decides what numbers to place in the n-th row! - _N. J. A. Sloane_, Nov 30 2002