Number of (1,0)-steps of weight 1 in all weighted lattice paths in L_n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =16a(5) =44a(6) =122a(7) =341a(8) =940a(9) =2581a(10) =7064a(11) =19258a(12) =52348a(13) =141935a(14) =383962a(15) =1036633a(16) =2793812a(17) =7517698a(18) =20200330a(19) =54209775a(20) =145309380a(21) =389091111a(22) =1040853492a(23) =2781908250a(24) =7429184976a(25) =19824925429a(26) =52866176702a(27) =140883978971a(28) =375216491080