Nim product 2*n.

Terms

a(0) =0a(1) =2a(2) =3a(3) =1a(4) =8a(5) =10a(6) =11a(7) =9a(8) =12a(9) =14a(10) =15a(11) =13a(12) =4a(13) =6a(14) =7a(15) =5a(16) =32a(17) =34a(18) =35a(19) =33a(20) =40a(21) =42a(22) =43a(23) =41a(24) =44a(25) =46a(26) =47a(27) =45a(28) =36a(29) =38