0,3

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

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

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

P. Kaski and P. R. J. \"Osterg{\aa}rd (Patric.Ostergard(AT)hut.fi), The Steiner triple systems of order 19

Index entries for sequences related to Steiner systems

There are 1197504000 STS's on 13 elements.

Indexed by A047241. Cf. A030128, A030129, A051390.

Sequence in context: A160269 A049394 A143169 this_sequence A007850 A158580 A097313

Adjacent sequences: A001198 A001199 A001200 this_sequence A001202 A001203 A001204

nonn,nice,hard

N. J. A. Sloane (njas(AT)research.att.com).