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 A046589 #9 Jul 02 2025 16:01:57 %S A046589 4,2,8,112,102,70,616,3432,6864,606,2080,10920,17810,23738,2686,28730, %T A046589 41548,23766,70278,13566,196,5320,102714,184110,352716,286824,1469650, %U A046589 11408,155848,4293962,5289448,2400,1378850,9583410,21915550,37442160 %N A046589 Distinct even numbers in writing first numerator and then denominator of each element of the 1/4-Pascal triangle (by row). %e A046589 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 A046589 Cf. A046563. %K A046589 tabf,nonn %O A046589 1,1 %A A046589 _Mohammad K. Azarian_ %E A046589 More terms from _James Sellers_, Dec 14 1999