a(n) = ceiling(10*log_2(n)).

Terms

a(0) =0a(1) =10a(2) =16a(3) =20a(4) =24a(5) =26a(6) =29a(7) =30a(8) =32a(9) =34a(10) =35a(11) =36a(12) =38a(13) =39a(14) =40a(15) =40a(16) =41a(17) =42a(18) =43a(19) =44a(20) =44a(21) =45a(22) =46a(23) =46a(24) =47a(25) =48a(26) =48a(27) =49a(28) =49a(29) =50