a(n) is the number of semi-meanders with n top arches that has no arch of length 1 at the ends of the top arch configuration and no arch of length 1 adjacent to the center of the top arch configuration.
A334615
a(n) is the number of semi-meanders with n top arches that has no arch of length 1 at the ends of the top arch configuration and no arch of length 1 adjacent to the center of the top arch configuration.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =2a(4) =0a(5) =10a(6) =6a(7) =72a(8) =86a(9) =602a(10) =982a(11) =5426a(12) =10558a(13) =51246a(14) =111602a(15) =500076a(16) =1177210a(17) =5001518a(18) =12462762a(19) =51003906a(20) =132711162a(21) =528420604a(22) =1422458280a(23) =5547419160a(24) =15347206464
External references
- oeis: A334615