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 A046572 #9 Jul 02 2025 16:01:57 %S A046572 1,1,1,4,5,2,19,2,35,1,259,2,483,1,1815,1,6864,1,52195,2,99671,1, %T A046572 382109,1,1469650,1,5668327,1,21915550,1,84913470,1,329624730,1, %U A046572 2563431075,2,4991324415,1,19463777025,1,75992317170,1,297026449005,1 %N A046572 First numerator and then denominator of the central elements of the 1/4-Pascal triangle (by row). %e A046572 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 A046572 Cf. A046563. %K A046572 nonn %O A046572 1,4 %A A046572 _Mohammad K. Azarian_ %E A046572 More terms from _James Sellers_, Dec 14 1999