Number of meanders in which first bridge is 5.

Terms

a(0) =3a(1) =3a(2) =7a(3) =11a(4) =28a(5) =57a(6) =155a(7) =353a(8) =1003a(9) =2458a(10) =7214a(11) =18575a(12) =55880a(13) =149183a(14) =457639a(15) =1255933a(16) =3914103a(17) =10978240a(18) =34663182a(19) =98953078a(20) =315884786a(21) =915008430a(22) =2948378068a(23) =8645874055a(24) =28084475514a(25) =83222134020a(26) =272235255044a(27) =814034370857