Number of 2-Motzkin meanders with catastrophes of length n.

Terms

a(0) =1a(1) =3a(2) =10a(3) =36a(4) =136a(5) =529a(6) =2095a(7) =8393a(8) =33885a(9) =137547a(10) =560544a(11) =2291181a(12) =9386584a(13) =38525224a(14) =158350133a(15) =651645511a(16) =2684323326a(17) =11066714500a(18) =45656997415a(19) =188475894929a(20) =778444106703