BIBDs

[Jim Nastos]

Hello all,

   I'm looking for some sequences related to "balanced 
incomplete block designs" (BIBDs) in the OEIS, and am
a little surprised that I cannot find any.

   Does anyone happen to know whether they exist in
the OEIS under other characterizations?

   (A BIBD is typically specified by a 5-tuple, and
the question of whether a given 5-tuple admits a BIBD
is quite nontrivial. I was hoping that there would
be sequences describing - in some way - which tuples
do or don't have a realization.)

Thanks,
Jim Nastos