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A051390 Number of nonisomorphic Steiner quadruple systems (SQS's) of order n. 7
1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 4, 0, 1054163 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,14
REFERENCES
CRC Handbook of Combinatorial Designs, 1996, circa p. 70.
A. Hartman and K. T. Phelps, Steiner quadruple systems, pp. 205-240 of Contemporary Design Theory, ed. Jeffrey H. Dinitz and D. R. Stinson, Wiley, 1992.
LINKS
Petteri Kaski, Patric R. J. Östergård (Patric.Ostergard(AT)hut.fi) and O. Pottonen, The Steiner quadruple systems of order 16, Journal of Combinatorial Theory, Series A, Volume 113, Issue 8, November 2006, Pages 1764-1770.
V. A. Zinoviev and D. V. Zinoviev, Classification of Steiner Quadruple Systems of order 16 and rank 14, [English translation from Russian], Problemy Peredachi Informatsii, 42 (No. 3, 2006), 59-72.
V. A. Zinoviev and D. V. Zinoviev, Classification of Steiner Quadruple Systems of order 16 and rank 14, Problems of Information Transmission, July-September 2006, Volume 42, Issue 3, pp 217-229; from [in Russian], Problemy Peredachi Informatsii, 42 (No. 3, 2006), 59-72.
FORMULA
a(n) = 0 unless n = 1 or n == 2 or 4 (mod 6).
EXAMPLE
There are 4 nonisomorphic SQS's on 14 points.
CROSSREFS
See A124120, A124119 for other versions of this sequence. The present entry is the official version.
Sequence in context: A306819 A336327 A327113 * A124120 A365952 A324803
KEYWORD
nonn,nice,hard
AUTHOR
STATUS
approved

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Last modified March 19 03:33 EDT 2024. Contains 370952 sequences. (Running on oeis4.)