This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A061439 #18 Jun 09 2019 21:14:46
%S A061439 2,4,9,21,46,99,215,464,999,2154,4641,9999,21544,46415,99999,215443,
%T A061439 464158,999999,2154434,4641588,9999999,21544346,46415888,99999999,
%U A061439 215443469,464158883,999999999,2154434690,4641588833,9999999999
%N A061439 Largest number whose cube has n digits.
%C A061439 a(n) + A181375(n) + A181377(n) + A181379(n) + A181381(n) + A181400(n) + A181402(n) + A181404(n) + A130130(n) = A002283(n).
%F A061439 a(n) = ceiling(10^(n/3)) - 1. - Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003
%e A061439 a(5) = 46 because 46^3 = 97336 has 5 digits, while 47^3 = 103823 has 6 digits.
%p A061439 Digits := 100:
%p A061439 A061439 := n->ceil(10^(n/3))-1:
%p A061439 seq (A061439(n), n=1..40);
%t A061439 t={}; i=0; Do[i=i+1; While[IntegerLength[i^3]<=n,i++]; AppendTo[t,i-1],{n,20}]; t (* _Jayanta Basu_, May 19 2013 *)
%Y A061439 a(n) is one more than the corresponding term of A018005. Cf. A061435.
%K A061439 nonn,base,easy
%O A061439 1,1
%A A061439 _Amarnath Murthy_, May 03 2001
%E A061439 More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001
%E A061439 Typo in Maple program fixed by _Martin Renner_, Jan 31 2011