A286756 Irregular triangle T(n,k) for 0 <= k < 5n/2: T(n,k) = number of vertices of the cube-connected cycle graph of order n that are at a distance k from a designated vertex.

1, 1, 1, 2, 2, 2, 1, 1, 3, 4, 6, 6, 3, 1, 1, 3, 5, 8, 11, 13, 13, 8, 2, 0, 1, 3, 6, 10, 16, 24, 31, 32, 23, 11, 3, 0, 1, 3, 6, 11, 18, 29, 43, 58, 72, 71, 47, 19, 5, 1, 0, 1, 3, 6, 12, 20, 34, 55, 83, 120, 154, 162, 131, 77, 29, 7, 2, 0

Offset: 1

Author

Andrew Howroyd, May 13 2017

Keywords

• nonn
• tabf

Comments

The cube-connected cycle graph of order n is a vertex transitive graph with n*2^n vertices and degree 3.

The radius of the graph is floor(5n/2)-1 for n<=3 and floor(5n/2)-2 for n>3.

Examples

			Triangle starts:
1, 1
1, 2, 2, 2, 1
1, 3, 4, 6, 6, 3, 1
1, 3, 5, 8,  11, 13, 13, 8, 2, 0
1, 3, 6, 10, 16, 24, 31, 32, 23, 11, 3, 0
1, 3, 6, 11, 18, 29, 43, 58, 72, 71, 47, 19, 5, 1, 0
1, 3, 6, 12, 20, 34, 55, 83, 120, 154, 162, 131, 77, 29, 7, 2, 0
...
The order 3 graph has 24 vertices. For k=1 to 6 there are 3, 4, 6, 6, 3, 1 vertices at a distance k from any vertex in the graph.
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..744
• Eric Weisstein's World of Mathematics, Cube-Connected Cycle Graph

Crossrefs

Row sums are A036289.

Cf. A192191.