a(n) = [ a(n-1)/a(1) ] + [ a(n-3)/a(3) ] + [ a(n-5)/a(5) ] + ..., for n >= 3.

Terms

a(0) =2a(1) =2a(2) =1a(3) =2a(4) =3a(5) =2a(6) =3a(7) =4a(8) =4a(9) =6a(10) =7a(11) =9a(12) =11a(13) =14a(14) =19a(15) =23a(16) =31a(17) =40a(18) =51a(19) =66a(20) =86a(21) =113a(22) =146a(23) =191a(24) =250a(25) =326a(26) =427a(27) =556a(28) =727a(29) =952