Number of ways a loop can cross two parallel roads 2n times.
A085973
Number of ways a loop can cross two parallel roads 2n times.
Terms
- a(0) =3a(1) =2a(2) =5a(3) =22a(4) =123a(5) =800a(6) =5754a(7) =44514a(8) =363893a(9) =3106288a(10) =27457050a(11) =249768040a(12) =2327398572a(13) =22135606604a(14) =214270565106
External references
- oeis: A085973