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 A061491 #9 Jun 17 2024 15:25:33
%S A061491 1,133,100330363,100000000300330000300660363,
%T A061491 100000000000000000000000000300000000300330000000000000300000000600660000300660363
%N A061491 a(1) = 1, a(n) = least number such that the concatenation a(n)a(n-1)...a(1) is a cube.
%H A061491 Robert Israel, <a href="/A061491/b061491.txt">Table of n, a(n) for n = 1..7</a>
%F A061491 a(n) = 10^(-3^(n-1)/2-1)*(Sum_{j=0..n-1}(10^(3^j/2))^3 - Sum_{j=0..n-2} (10^(3^j/2))^3). - _Robert Israel_, Jun 17 2024
%e A061491 a(1) = 1, a(2) = 133, a(2)a(1) = 1331 = 11^3.
%p A061491 f:= proc(n) local j; 10^(-3^(n-1)/2-1)*(add(10^(3^j/2),j=0..n-1)^3 - add(10^(3^j/2),j=0..n-2)^3) end proc:
%p A061491 seq(f(n),n=1..5); # _Robert Israel_, Jun 17 2024
%Y A061491 Cf. A061359, A061361, A061363.
%K A061491 base,nonn
%O A061491 1,2
%A A061491 _Amarnath Murthy_, May 06 2001
%E A061491 More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Nov 06 2001
%E A061491 Corrected by _Robert Israel_, Jun 17 2024