Number of Steiner quadruple systems (SQS's) of order n.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =0a(5) =0a(6) =0a(7) =30a(8) =0a(9) =2520a(10) =0a(11) =0a(12) =0a(13) =37362124800a(14) =0a(16) =0a(17) =0a(18) =0