Triangle by rows T(n,k), showing the number of meanders with length (n+1)*4 and containing (k+1)*4 Ls and (n-k)*4 Rs, where Ls and Rs denote arcs of equal length and a central angle of 90 degrees which are positively or negatively oriented.
A197653
Triangle by rows T(n,k), showing the number of meanders with length (n+1)*4 and containing (k+1)*4 Ls and (n-k)*4 Rs, where Ls and Rs denote arcs of equal length and a central angle of 90 degrees which are positively or negatively oriented.
Terms
- a(0) =1a(1) =4a(2) =1a(3) =15a(4) =30a(5) =1a(6) =40a(7) =324a(8) =120a(9) =1a(10) =85a(11) =2080a(12) =3120a(13) =340a(14) =1a(15) =156a(16) =9375a(17) =40000a(18) =18750a(19) =780a(20) =1a(21) =259a(22) =32886a(23) =328125a(24) =437500a(25) =82215a(26) =1554a(27) =1a(28) =400a(29) =96040
External references
- oeis: A197653