a(n) is the forgotten index of the Lucas cube Lambda(n).

Terms

a(0) =0a(1) =10a(2) =30a(3) =112a(4) =300a(5) =840a(6) =2044a(7) =4864a(8) =10944a(9) =23960a(10) =50908a(11) =105840a(12) =215748a(13) =432656a(14) =855240a(15) =1669568a(16) =3223404a(17) =6162552a(18) =11678540a(19) =21957440a(20) =40988976a(21) =76019944a(22) =140155100a(23) =256995936a(24) =468887700a(25) =851538064a(26) =1539858168a(27) =2773522192a(28) =4977094956a(29) =8900629800