|
%I #9 Dec 05 2013 19:55:10
%S 1,10,105,1035,10011,100128,1000405,10001628,100005153,1000006281,
%T 10000020331,100000404505,1000001326005,10000002437316,
%U 100000012392316,1000000042485480,10000000037150046,100000000000018810,1000000000179470703,10000000002237948990
%N Smallest n-digit triangular number.
%F Triangular number with index given by A068092.
%t 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 Cf. A068092, A068094, A095863, A095864, A095865, A095866.
%K base,easy,nonn
%O 1,2
%A _Amarnath Murthy_, Feb 19 2002
%E More terms from _Sascha Kurz_, Mar 06 2002
|
