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 A046220 #9 Jul 02 2025 16:01:56 %S A046220 1,2,3,5,7,11,9,27,20,13,19,67,40,15,51,105,147,17,33,78,126,83,111, %T A046220 204,273,21,305,315,477,546,23,123,407,935,792,1023,25,73,265,671, %U A046220 2519,1815,2046,171,338,936,3861,6149,29,99,847,1274,5733,5005,13871,7722 %N A046220 Distinct numbers in writing first numerator and then denominator of 1/2-Pascal triangle (by row). %e A046220 1/1; 1/1 1/1; 1/1 1/2 1/1; 1/1 3/2 3/2 1/1; 1/1 5/2 3/1 5/2 1/1; 1/1 7/2 11/2 11/2 7/2 1/1; 1/1 9/2 9/1 11/1 9/1 9/2 1/1; 1/1 11/2 27/2 20/1 20/1 27/2 11/2 1/1; ... %Y A046220 Cf. A046213. %K A046220 tabf,nonn,easy %O A046220 1,2 %A A046220 _Mohammad K. Azarian_ %E A046220 More terms from _James Sellers_, Dec 13 1999