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 A246565 #10 Aug 31 2014 02:00:41 %S A246565 1,1,2,3,6,9,20,31,67,115,238,406,880,1494,3118,5568,11408,20092, %T A246565 41938,73687,151529,272359,552611,987277,2033173,3617167,7371745, %U A246565 13318869,26991289,48496985,99264686,177917588,362349258,655925568,1331038563,2401097768,4913906801,8844673793,18046697901,32720071992,66666578597 %N A246565 Number of rooted ordered trees with n non-root nodes such that the branch lengths are weakly increasing. %H A246565 Joerg Arndt, <a href="/A246565/a246565.txt">All trees for 0 <= n <= 7</a> %e A246565 The a(4) = 6 such trees are: %e A246565 : %e A246565 : 1: %e A246565 : [ 1 1 1 1 ] %e A246565 : [ 0 0 0 0 ] %e A246565 : %e A246565 : O--o %e A246565 : .--o %e A246565 : .--o %e A246565 : .--o %e A246565 : %e A246565 : %e A246565 : 2: %e A246565 : [ 1 1 2 ] %e A246565 : [ 0 0 0 ] %e A246565 : %e A246565 : O--o %e A246565 : .--o %e A246565 : .--o--o %e A246565 : %e A246565 : %e A246565 : 3: %e A246565 : [ 1 3 ] %e A246565 : [ 0 0 ] %e A246565 : %e A246565 : O--o %e A246565 : .--o--o--o %e A246565 : %e A246565 : %e A246565 : 4: %e A246565 : [ 2 2 ] %e A246565 : [ 0 0 ] %e A246565 : %e A246565 : O--o--o %e A246565 : .--o--o %e A246565 : %e A246565 : %e A246565 : 5: %e A246565 : [ 2 2 ] %e A246565 : [ 0 1 ] %e A246565 : %e A246565 : O--o--o %e A246565 : .--o--o %e A246565 : %e A246565 : %e A246565 : 6: %e A246565 : [ 4 ] %e A246565 : [ 0 ] %e A246565 : %e A246565 : O--o--o--o--o %e A246565 : %e A246565 See the Arndt link for all trees for 0 <= n <= 7. %Y A246565 Cf. A000108 (all trees), A246566 (descending branch lengths), A193196, A192243. %K A246565 nonn %O A246565 0,3 %A A246565 _Joerg Arndt_, Aug 30 2014