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 A046573 #9 Jul 02 2025 16:01:57 %S A046573 1,1,4,1,2,5,2,19,1,35,2,259,1,483,1,1815,1,6864,2,52195,1,99671,1, %T A046573 382109,1,1469650,1,5668327,1,21915550,1,84913470,1,329624730,2, %U A046573 2563431075,1,4991324415,1,19463777025,1,75992317170,1,297026449005,1 %N A046573 First denominator and then numerator of the central elements of the 1/4-Pascal triangle (by row). %e A046573 1/1; 1/1 1/1; 1/1 1/4 1/1; 1/1 5/4 5/4 1/1; 1/1 9/4 5/2 9/4 1/1; 1/1 13/4 19/4 19/4 13/4 1/1; 1/1 17/4 8/1 19/2 8/1 17/4 1/1; 1/1 21/4 49/4 35/2 35/2 49/4 21/4 1/1; ... %Y A046573 Cf. A046563. %K A046573 nonn %O A046573 1,3 %A A046573 _Mohammad K. Azarian_ %E A046573 More terms from _James Sellers_, Dec 14 1999