Number of (1,1) steps in all peakless Motzkin paths of length n.

Terms

a(0) =1a(1) =3a(2) =8a(3) =22a(4) =58a(5) =151a(6) =392a(7) =1013a(8) =2612a(9) =6728a(10) =17318a(11) =44564a(12) =114671a(13) =295099a(14) =759576a(15) =1955657a(16) =5036741a(17) =12976355a(18) =33443190a(19) =86221745a(20) =222371926a(21) =573713958a(22) =1480677048a(23) =3822708372a(24) =9872424913a(25) =25504336609a(26) =65907869404a(27) =170368399138