a(n) = coefficient of 2^(1/3) in the expansion of (2^(1/3) + 2^(2/3))^n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =6a(4) =18a(5) =48a(6) =144a(7) =396a(8) =1152a(9) =3240a(10) =9288a(11) =26352a(12) =75168a(13) =213840a(14) =609120a(15) =1734048a(16) =4937760a(17) =14059008a(18) =40030848a(19) =113980608a(20) =324539136a(21) =924068736a(22) =2631118464a(23) =7491647232a(24) =21331123200a(25) =60736594176a(26) =172936622592a(27) =492406304256