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A160772 Number of nodes (or order) of a graph model obtained using an automata scheme on sets of order prime(n) >= 5 and in which all not halt states are linked by arcs (edges). 0
13, 31, 91, 133, 241, 307, 463, 757, 871, 1261, 1561, 1723, 2071, 2653, 3307, 3541, 4291, 4831, 5113, 6007, 6643, 7657, 9121, 9901, 10303, 11131, 11557, 12433, 15751, 16771, 18361, 18907, 21757, 22351, 24181, 26083, 27391, 29413, 31507, 32221, 35911, 36673 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Special graph models were constructed (Ibrahim, 2009) using an automata scheme involving some transition function defined on the Special (123)-avoiding permutation patterns reported by Ibrahim and Audu (2005; Ibrahim, 2008). The order of these special variety of graph models represents an improvement of the earlier models (Ibrahim 2008) in the study of the degree/diameter problems as used in circuit designs and analysis. The sequence represents the number of nodes (order) in this latest variety of graph models for primes >= 5.

REFERENCES

A. A. Ibrahim, Some Transformation Schemes Involving the Special (132) - avoiding Permutation Patterns and a Binary Coding: An Algorithmic Approach Asian Journal of Algebra 1 (1):10-14, Asian Network for Scientific Information (ANSI), Pakistan (2008).

A. A. Ibrahim and M. S. Audu, Some Group theoretic Properties of Certain Class of (123) and (132)-Avoiding Patterns Numbers: an enumeration scheme, African journal Natural Sciences Vol. 8: 79-84 (2005).

A. A. Ibrahim, and M. S. Audu, On Stable Variety of Cayley Graphs For Efficient Interconnection Networks Proceedings of Annual National Conference of Mathematical Association of Nigeria (MAN) held at Federal College of Education Technical, Gusau 26th- 30th August, 2008:156-161 (2008).

LINKS

Table of n, a(n) for n=3..44.

FORMULA

a(n) = (prime(n)-2)*(prime(n)-1) + 1.

EXAMPLE

For prime(3) = 5: a(n) = (3)(4)+1 = 13; for prime(4) = 7: a(n) = (5)(6)+1 = 31

MATHEMATICA

Table[(Prime[n] - 2) (Prime[n] - 1) + 1, {n, 3, 50}] (* T. D. Noe, Dec 30 2012 *)

CROSSREFS

Cf. A128929, A040976.

Sequence in context: A211116 A107288 A095379 * A039403 A062339 A043226

Adjacent sequences:  A160769 A160770 A160771 * A160773 A160774 A160775

KEYWORD

nonn

AUTHOR

Aminu Alhaji Ibrahim, Jun 09 2009

EXTENSIONS

Terms changed by T. D. Noe, Dec 30 2012

STATUS

approved

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Last modified December 19 22:28 EST 2014. Contains 252240 sequences.