Triangle by rows T(n,k), showing the number of meanders with length (n+1)*6 and containing (k+1)*6 Ls and (n-k)*6 Rs, where Ls and Rs denote arcs of equal length and a central angle of 60 degrees which are positively or negatively oriented.
A197655
Triangle by rows T(n,k), showing the number of meanders with length (n+1)*6 and containing (k+1)*6 Ls and (n-k)*6 Rs, where Ls and Rs denote arcs of equal length and a central angle of 60 degrees which are positively or negatively oriented.
Terms
- a(0) =1a(1) =6a(2) =1a(3) =63a(4) =126a(5) =1a(6) =364a(7) =4374a(8) =1092a(9) =1a(10) =1365a(11) =85120a(12) =127680a(13) =5460a(14) =1a(15) =3906a(16) =984375a(17) =6000000a(18) =1968750a(19) =19530a(20) =1a(21) =9331a(22) =7562646a(23) =157828125a(24) =210437500a(25) =18906615a(26) =55986a(27) =1a(28) =19608a(29) =42824236
External references
- oeis: A197655