Number of, not necessarily connected, regular simple graphs on n vertices with girth exactly 4.
A198314
Number of, not necessarily connected, regular simple graphs on n vertices with girth exactly 4.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =0a(6) =1a(7) =0a(8) =4a(9) =1a(10) =8a(11) =3a(12) =37a(13) =33a(14) =335a(15) =1610a(16) =17985a(17) =193911a(18) =2867313a(19) =32674066a(20) =1581626531a(21) =6705889862
External references
- oeis: A198314