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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

Table of n, a(n) for n=1..16.

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.

Index entries for sequences related to Steiner systems

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.

Cf. A030129, A001201, A030128.

Sequence in context: A306819 A336327 A327113 * A124120 A324803 A320742

Adjacent sequences:  A051387 A051388 A051389 * A051391 A051392 A051393

KEYWORD

nonn,nice,hard

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified May 18 19:25 EDT 2021. Contains 344002 sequences. (Running on oeis4.)