%I #13 Mar 09 2015 11:38:29
%S 18,20,29,46,72,74,76,86,107,111,115,127,136,143,144,156,159,162,164,
%T 172,178,180,181,190,205,207,213,228,271,275,282,288,312,320,321,323,
%U 328,339,340,354,358,365,376,384
%N Positions of 3's in the decimal expansion of exp(1).
%H Vincenzo Librandi, <a href="/A054279/b054279.txt">Table of n, a(n) for n = 1..1000</a>
%t Flatten[Position[RealDigits[E,10,400][[1]],3]] (* _Harvey P. Dale_, Mar 06 2011 *)
%K nonn,base
%O 1,1
%A _Simon Plouffe_, Feb 20 2000
%E Changed offset from 0 to 1 by _Vincenzo Librandi_, Oct 07 2013