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 A241907 #22 Feb 18 2019 05:35:21
%S A241907 1,2,3,5,7,9,11,14,17,20,23,26,29,33,36,40,44,48,52,56,60,65,69,74,78,
%T A241907 83,88,93,98,103,108,114,119,124,130,136,141,147,153,159,165,171,177,
%U A241907 183,189,196,202,209,215,222,229,235,242,249,256,263,270,277,284,292,299,306,314,321,329,336,344,352,360,367,375,383,391,399,408,416,424,432,441,449,457,466,474,483,492,500,509,518,527,536,545,554,563,572,581,590,599,609,618,627,637,646,656,665,675,685,694,704,714,724,734,744,753,764,774,784,794,804,814,825,835,845,856,866,877,887,898,908,919,930,940,951,962,973,984,995,1006
%N A241907 a(n) = floor( Catalan(2*n) / Catalan(n)^2 ).
%C A241907 This sequence is (roughly) the relative size of the Jones monoid J_n to its minimal ideal. Equivalently, this is roughly the reciprocal of the proportion of Dyck words of length 4n which can be factorized into two Dyck words, each of length 2n.
%H A241907 Wikipedia, <a href="http://en.wikipedia.org/wiki/Dyck_word#Applications_in_combinatorics">Dyck word</a>
%F A241907 a(n) = floor( Catalan( 2*n ) / Catalan(n)^2 ).
%p A241907 Digits:=200:
%p A241907 C:=n->binomial(2*n,n)/(n+1); f:=n->floor(C(2*n)/C(n)^2);[seq(f(n),n=0..100)]; # _N. J. A. Sloane_, May 21 2014
%t A241907 Table[Floor[CatalanNumber[2n]/CatalanNumber[n]^2],{n,0,140}] (* _Harvey P. Dale_, Oct 04 2015 *)
%Y A241907 Cf. A000108.
%K A241907 nonn,easy
%O A241907 0,2
%A A241907 _Nick Loughlin_, May 01 2014
%E A241907 Corrected by _Harvey P. Dale_, Oct 04 2015