a(n) = (A000045(n)+A173432(n))/2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =3a(5) =4a(6) =7a(7) =11a(8) =18a(9) =28a(10) =45a(11) =72a(12) =117a(13) =189a(14) =306a(15) =494a(16) =799a(17) =1292a(18) =2091a(19) =3383a(20) =5474a(21) =8856a(22) =14329a(23) =23184a(24) =37513a(25) =60697a(26) =98210a(27) =158906a(28) =257115a(29) =416020