A187567 - OEIS

%I #18 Nov 25 2018 11:56:22

%S 0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0,18,0,0

%N Number of Steiner Systems S(2,4,n).

%C S(2,4,n) exists if and only if n == 1 or 4 (mod 12).

%C a(28) >= 4653.

%H Colin Reid and Alex Rosa, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/DS18">Steiner systems S(2,4,v) - a survey</a>, Electronic Journal of Combinatorics, Dynamic Survey DS18, Feb 01 2010.

%H E. Spence, <a href="https://doi.org/10.1002/(SICI)1520-6610(1996)4:4%3C295::AID-JCD6%3E3.0.CO;2-A">The complete classification of Steiner Systems S(2,4,25)</a>, J. Combin. Designs, 4 (1996), 295-300.

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

%Y Cf. A187585, A001201, A030129.

%K nonn,more

%O 1,25

%A _N. J. A. Sloane_, Mar 11 2011