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 A046203 #10 Jul 02 2025 16:01:56 %S A046203 2,2,6,4,12,12,4,20,30,20,6,30,60,60,30,6,42,140,42,8,56,168,280,280, %T A046203 168,56,8,72,252,504,630,504,252,72,10,90,360,840,1260,1260,840,360, %U A046203 90,10,110,1320,2310,2772,2310,1320,110,12,132,660,1980,3960,5544,5544 %N A046203 Even numbers in the triangle of denominators in Leibniz's Harmonic Triangle. %D A046203 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 83, Problem 25. %e A046203 1/1; 1/2, 1/2; 1/3, 1/6, 1/3; 1/4, 1/12, 1/12, 1/4; 1/5, 1/20, 1/30, 1/20, 1/5; ... %Y A046203 Cf. A003506. %K A046203 tabf,nonn,easy %O A046203 1,1 %A A046203 _Mohammad K. Azarian_ %E A046203 More terms from _James Sellers_, Dec 13 1999