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 A068093 #9 Dec 05 2013 19:55:10 %S A068093 1,10,105,1035,10011,100128,1000405,10001628,100005153,1000006281, %T A068093 10000020331,100000404505,1000001326005,10000002437316, %U A068093 100000012392316,1000000042485480,10000000037150046,100000000000018810,1000000000179470703,10000000002237948990 %N A068093 Smallest n-digit triangular number. %F A068093 Triangular number with index given by A068092. %t A068093 triInverse[n_] := Floor[(Sqrt[1 + 8*n] - 1)/2]; tri[n_] := n*(n+1)/2; Table[tri[1 + triInverse[10^(n-1) - 1]], {n, 20}] (* _T. D. Noe_, Jul 27 2012 *) %Y A068093 Cf. A068092, A068094, A095863, A095864, A095865, A095866. %K A068093 base,easy,nonn %O A068093 1,2 %A A068093 _Amarnath Murthy_, Feb 19 2002 %E A068093 More terms from _Sascha Kurz_, Mar 06 2002