Number of n-element sets of singletons or pairs of distinct elements of {1..n}, or loop graphs with n edges, such that it is not possible to choose a different element from each.
A368596
Number of n-element sets of singletons or pairs of distinct elements of {1..n}, or loop graphs with n edges, such that it is not possible to choose a different element from each.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =3a(4) =66a(5) =1380a(6) =31460a(7) =800625a(8) =22758918a(9) =718821852a(10) =25057509036a(11) =957657379437
External references
- oeis: A368596