A128929 Diameter of a special type of regular graph of degree 4 whose order maintain an increase in form of an arithmetic progression.

1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21

Offset: 4

Author

Aminu Alhaji Ibrahim, Apr 25 2007

Keywords

• nonn

Examples

			f(D4,5)=1 when order=4, f(D4,5)=1 when order=5, f(D)=f(D4,5)+1=1+1=2 when order is 5+1=6
		

References

• Claude C.S. and Dinneen M.J (1998), Group-theoretic methods for designing networks, Discrete mathematics and theoretical computer science, Research report
• Comellas, F. and Gomez, J. (1995), New large graphs with given degree and diameter, in Proceedings of the seventh quadrennial international conference on the theory and applications of graphs, Volume 1: pp. 222-233
• Ibrahim, A., A. (2007), A stable variety of Cayley graphs (in preparation)

Links

• Eric Weisstein's World of Mathematics, Graph Thickness
• Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 1, -1).

Crossrefs

Cf. A123642.

First differences of A186347.

Formula

f(D4,5)=1: Order =4,5; f(D)= f(D4,5)+n: order=5+n, n=1,2,...

I am assuming this sequence is just Floor[(n+5)/4]... [From Eric W. Weisstein, Sep 09 2008]