Number of weighted lattice paths in L_n having no (1,0)-steps of weight 2 at level 0.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =7a(5) =15a(6) =35a(7) =83a(8) =197a(9) =473a(10) =1145a(11) =2787a(12) =6819a(13) =16759a(14) =41345a(15) =102341a(16) =254075a(17) =632437a(18) =1577967a(19) =3945517a(20) =9884379a(21) =24806201a(22) =62355121a(23) =156974319a(24) =395712759a(25) =998809135a(26) =2524043569a(27) =6385400005a(28) =16170553755a(29) =40990092629