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 A241721 #4 Apr 28 2014 09:46:54 %S A241721 1,1,2,3,15,16,29,41,65,144,179,269,382,549,739,1286,1564,2254,2978, %T A241721 4124,5304,7264,10157,12941,17027,22194,28663,36884,47306,59837,79467, %U A241721 98114,125117,156392,198113,244710,307908,378429,471337,588642,721300,884498 %N A241721 Number of compositions of n into distinct parts with exactly two descents. %H A241721 Alois P. Heinz, <a href="/A241721/b241721.txt">Table of n, a(n) for n = 6..1000</a> %e A241721 a(9) = 3: [6,2,1], [5,3,1], [4,3,2]. %e A241721 a(10) = 15: [5,4,1], [7,2,1], [6,3,1], [5,3,2], [4,1,3,2], [2,1,4,3], [4,3,1,2], [4,2,3,1], [2,4,3,1], [1,4,3,2], [3,1,4,2], [3,2,4,1], [3,4,2,1], [4,2,1,3], [3,2,1,4]. %Y A241721 Column k=2 of A241719. %K A241721 nonn %O A241721 6,3 %A A241721 _Alois P. Heinz_, Apr 27 2014