a(n) is the least positive multiple of 2*n-1 containing only the digits 0 and 1 in base n.

Terms

a(0) =1a(1) =3a(2) =10a(3) =21a(4) =126a(5) =253a(6) =351a(7) =585a(8) =6562a(9) =11001a(10) =14763a(11) =22609a(12) =28575a(13) =41175a(14) =50866a(15) =69905a(16) =1419858a(17) =1994545a(18) =2482959a(19) =3368001a(20) =4084543a(21) =5388373a(22) =6449040a(23) =8308801a(24) =9765651a(25) =12338379a(26) =14368618a(27) =17847005a(28) =20512020a(29) =25110931