Triangle read by rows: T(n,k) is the number of single loop solutions formed by n proper arches (connecting odd vertices to even vertices in the range 1 to 2n) above the x axis, k of which connect an odd vertex to a higher even vertex, with a rainbow of n arches below the x axis.
A244312
Triangle read by rows: T(n,k) is the number of single loop solutions formed by n proper arches (connecting odd vertices to even vertices in the range 1 to 2n) above the x axis, k of which connect an odd vertex to a higher even vertex, with a rainbow of n arches below the x axis.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =0a(4) =2a(5) =0a(6) =0a(7) =2a(8) =4a(9) =0a(10) =0a(11) =4a(12) =16a(13) =4a(14) =0a(15) =0a(16) =4a(17) =48a(18) =60a(19) =8a(20) =0a(21) =0a(22) =8a(23) =160a(24) =384a(25) =160a(26) =8a(27) =0a(28) =0a(29) =8
External references
- oeis: A244312