Number of Dyck paths of semilength n avoiding the pattern U^4 D^4 U D.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =41a(6) =110a(7) =245a(8) =450a(9) =739a(10) =1126a(11) =1625a(12) =2250a(13) =3015a(14) =3934a(15) =5021a(16) =6290a(17) =7755a(18) =9430a(19) =11329a(20) =13466a(21) =15855a(22) =18510a(23) =21445a(24) =24674a(25) =28211a(26) =32070a(27) =36265a(28) =40810a(29) =45719