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A053555
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Number of distinct parameter sets (v,k,lambda) for Abelian difference sets of order n = k-lambda with 1 <= lambda <= n-1.
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0
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1, 2, 3, 2, 1, 2, 1, 2, 5, 0, 2, 1, 1, 0, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,2
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REFERENCES
| D. Jungnickel, Difference Sets, Chapter 7 of J. H. Dinitz and D R. Stinson, Contemporary Design Theory, Wiley, 1992, see Appendix.
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EXAMPLE
| The 3 parameter sets for order 4 are (v,k,lambda) = (21,5,1), (16,6,2) and (15,7,3).
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CROSSREFS
| Sequence in context: A137927 A084311 A026490 * A124160 A002175 A170823
Adjacent sequences: A053552 A053553 A053554 * A053556 A053557 A053558
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KEYWORD
| nonn,nice,hard
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jan 17 2000
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EXTENSIONS
| a(16) is not known.
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