a(n) is the largest integer whose cube has n digits and first digit 1, except that a(2)=2.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =27a(5) =58a(6) =125a(7) =271a(8) =584a(9) =1259a(10) =2714a(11) =5848a(12) =12599a(13) =27144a(14) =58480a(15) =125992a(16) =271441a(17) =584803a(18) =1259921a(19) =2714417a(20) =5848035a(21) =12599210a(22) =27144176a(23) =58480354a(24) =125992104a(25) =271441761a(26) =584803547a(27) =1259921049a(28) =2714417616a(29) =5848035476