Number of dispersed Dyck prefixes of length 2n and height n.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =36a(5) =90a(6) =286a(7) =728a(8) =2380a(9) =6120a(10) =20349a(11) =52668a(12) =177100a(13) =460460a(14) =1560780a(15) =4071600a(16) =13884156a(17) =36312408a(18) =124403620a(19) =326023280a(20) =1121099408a(21) =2942885946a(22) =10150595910a(23) =26681566392a(24) =92263734836a(25) =242799302200a(26) =841392966470