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A030128 Steiner triple systems (STS's) on n elements. 6


%S 1,0,1,0,0,0,30,0,840,0,0,0,1197504000,0,60281712691200,0,0,0,

%T 1348410350618155344199680000

%N Steiner triple systems (STS's) on n elements.

%D L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 304.

%D CRC Handbook of Combinatorial Designs, 1996, p. 70.

%H Yue Guan, Minjia Shi, Denis S. Krotov, <a href="https://arxiv.org/abs/1905.09081">The Steiner triple systems of order 21 with a transversal subdesign TD(3,6)</a>, arXiv:1905.09081 [math.CO], 2019.

%H Petteri Kaski and Patric R. J. Östergård, <a href="http://dx.doi.org/10.1090/S0025-5718-04-01626-6">The Steiner triple systems of order 19</a>, Math. Comp. 73 (2004), 2075-2092.

%H Minjia Shi, Li Xu, Denis S. Krotov, <a href="https://arxiv.org/abs/1806.00009">The number of the non-full-rank Steiner triple systems</a>, arXiv:1806.00009 [math.CO], 2018.

%H <a href="/index/St#Steiner">Index entries for sequences related to Steiner systems</a>

%Y Cf. A001201, A030129, A051390.

%K nonn,nice,hard

%O 1,7

%A _N. J. A. Sloane_

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Last modified June 21 16:42 EDT 2021. Contains 345365 sequences. (Running on oeis4.)