Number of weighted lattice paths B(n) having no uhd and no uHd strings.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =14a(6) =30a(7) =64a(8) =141a(9) =316a(10) =713a(11) =1626a(12) =3740a(13) =8659a(14) =20176a(15) =47274a(16) =111302a(17) =263201a(18) =624860a(19) =1488736a(20) =3558412a(21) =8530533a(22) =20505468a(23) =49413242a(24) =119347708a(25) =288873639a(26) =700582008a(27) =1702190653a(28) =4142880297a(29) =10099352082