Number of meanders of order n, with 1-1 cut.

Terms

a(0) =0a(1) =0a(2) =4a(3) =24a(4) =152a(5) =1056a(6) =7884a(7) =62336a(8) =516060a(9) =4435888a(10) =39338456a(11) =358164768a(12) =3335087752a(13) =31663393880a(14) =305740631660