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A053555 Number of distinct parameter sets (v,k,lambda) for Abelian difference sets of order n = k-lambda with 1 <= lambda <= n-1. 0
1, 2, 3, 2, 1, 2, 1, 2, 5, 0, 2, 1, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

REFERENCES

D. Jungnickel, Difference Sets, Chapter 7 of J. H. Dinitz and D R. Stinson, Contemporary Design Theory, Wiley, 1992, see Appendix.

LINKS

Table of n, a(n) for n=2..16.

EXAMPLE

The 3 parameter sets for order 4 are (v,k,lambda) = (21,5,1), (16,6,2) and (15,7,3).

CROSSREFS

Sequence in context: A321864 A084311 A026490 * A124160 A265847 A260342

Adjacent sequences:  A053552 A053553 A053554 * A053556 A053557 A053558

KEYWORD

nonn,nice,hard

AUTHOR

N. J. A. Sloane, Jan 17 2000

EXTENSIONS

a(16) is not known.

STATUS

approved

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Last modified February 21 20:19 EST 2019. Contains 320377 sequences. (Running on oeis4.)