  The lonely singles sequence represents the number of noncrossing partitions
of the finite set {1,. .. , n} in which no pair of singletons {i} and {j} can
be merged into the pair {i, j} so that the partition stays noncrossing. The
marriageable singles sequence represents the number of all the other
noncrossing partitions and is the difference between the Catalan numbers
sequence and the lonely singles sequence. The 14 first terms of these sequences
are given, as well as some of their properties. These sequences appear when one
wants to count the number of ways to cross simultaneously certain road
intersections.
