%I #7 Mar 29 2015 16:32:51

%S 3,6,12,24,48,816,16212,212424,424848,84816816,1681621216212,

%T 21216212424212424,424212424848424848,8484248481681684816816,

%U 1681684816816212162121681621216212,21216212168162121621242421242421216212424212424

%N Begin with 3, multiply each digit by 2, keeping the memory of the groupings of the preceding digits.

%F d*2, beginning with 3.

%e Read a(3)=12 which produces a(4)=24 because 1*2=2 and 2*2=4.

%t Flatten[ NestList[ Function[x, FromDigits[ Flatten[ IntegerDigits[2IntegerDigits[ x]]] ]], 3, 15]] (* _Robert G. Wilson v_, Feb 21 2005 *)

%K base,easy,nonn

%O 1,1

%A _Alexandre Wajnberg_ and _Eric Angelini_, Feb 18 2005

%E More terms from _Robert G. Wilson v_, Feb 21 2005