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A128984 Degree of the special subgraph of Cayley graph constructed using the special (123)-avoiding and (132)-avoiding permutation patterns as generators. 0
2, 4, 6, 10, 12, 16, 18, 22, 28, 30, 36, 40, 42, 46, 50, 52, 56, 58, 60, 66, 70, 72, 76, 78, 82, 86, 88, 90, 96, 100, 102, 106, 110, 112, 116, 118, 122, 128, 130, 136, 140, 142, 146, 148, 150, 156, 160, 166, 170, 172, 178, 180, 182, 186, 190, 192, 196, 198, 200, 202 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

This sequence is constructed using a special veriety of subgraphs of Cayley graphs in order for a study of the degree/diameter problem.

REFERENCES

Ibrahim A.A. and Audu M.S.(2005) Some Group Theoretic Properties of Certain Class of (123) and (132)-Avoiding Patterns of Numbers: An Enumeration Scheme: An enumeration Scheme, African Journal of Natural Sciences, Vol. 8:79-84

Ibrahim A.A. (2006) A Counting Scheme And Some Algebraic Properties of A Class of Special Permutation Patterns. (in preparation)

Ibrahim A.A. (2005) On the Combinatorics of Succession In A 5-element Sample Abacus Journal of Mathematical Association of Nigeria Vol. 32, No. 2B:410-415

LINKS

Table of n, a(n) for n=3..62.

FORMULA

Recursion relation:f(0)=2, f(2)=4, f(3)=6, f(4)=12, f(5)=f(1)+f(2)+f(3)+f(4)/f(0), f(n)=f(n-1)+f(n-2)+f(n-3)+f(n-4)-f(n-5)/f(0)-f(n-5), n>5 and provided the difference between consecutive numbers (before and at the start of the addition) does not exceed four digits. If however, this difference (m-(m-1)<=4 the f(n)=f(n-1)+f(n-2)+f(n-3)+f(n-4)/f(0)-f(n-4). [Indices need to be changed to match the offset. - R. J. Mathar, Dec 04 2011]

CROSSREFS

Cf. A123642, A128929.

Sequence in context: A249434 A249425 A085477 * A249427 A075728 A146886

Adjacent sequences:  A128981 A128982 A128983 * A128985 A128986 A128987

KEYWORD

nonn,uned

AUTHOR

Aminu Alhaji Ibrahim, Apr 30 2007

EXTENSIONS

An obviously incorrect prime formula deleted. - R. J. Mathar, Dec 04 2011

STATUS

approved

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Last modified October 17 18:58 EDT 2019. Contains 328127 sequences. (Running on oeis4.)