Number of ways a loop can cross three roads meeting in a Y n times.
A085919
Number of ways a loop can cross three roads meeting in a Y n times.
Terms
- a(0) =3a(1) =0a(2) =3a(3) =1a(4) =9a(5) =6a(6) =45a(7) =42a(8) =279a(9) =320a(10) =1977a(11) =2610a(12) =15306a(13) =22404a(14) =126300a(15) =200158a(16) =1093515a(17) =1846314a(18) =9830547a(19) =17481864
External references
- oeis: A085919