%I #16 Jan 08 2021 12:59:46
%S 1,2,3,4,5,6,7,8,9,16,10,11,12,13,14,17,18,19,23,25,27,32,49,53,64,81,
%T 128,256,512,65536,15,20,21,22,24,26,28,29,31,34,36,37,38,41,43,46,48,
%U 50,54,59,61,67,83,97,98,103,106,121,125,131,162,169,227,241,243,289
%N Triangle in which k-th row lists natural number values for the collection of riffs with k nodes.
%H Jon Awbrey, <a href="https://oeis.org/wiki/Riffs_and_Rotes">Riffs and Rotes</a>
%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%e k | natural numbers n such that |riff(n)| = k
%e 0 | 1;
%e 1 | 2;
%e 2 | 3, 4;
%e 3 | 5, 6, 7, 8, 9, 16;
%e 4 | 10, 11, 12, 13, 14, 17, 18, 19, 23, 25, 27, 32, 49, 53, 64, 81, 128, 256, 512, 65536;
%e The natural number values for the riffs with at most 3 pts are as follows (x = root):
%e .................o.......o..o.......o
%e .................|.......^..|.......^
%e .................v.......|..v.......|
%e ...........o..o..o....o..o..o..o.o..o
%e ...........|..^..|....|..|..^..|.^..^
%e ...........v..|..v....v..v..|..v/...|
%e Riff:...x;.x,.x;.x,.x.x,.x,.x,.x,...x;
%e Value:..2;.3,.4;.5,..6.,.7,.8,.9,..16;
%Y Cf. A061396, A062860.
%K nonn,tabf
%O 0,2
%A _Jon Awbrey_, Jun 23 2001