%I #3 Mar 30 2012 17:33:53
%S 10,100,10000,1000000,1000000000000,10000000000000000,
%T 1000000000000000000,1000000000000000000000000000000
%N Even superperfect numbers written in base 2.
%C Also, superperfect numbers (A019279) written in base 2 (If there are no odd perfect numbers).
%C Also, concatenation of "1" and A090748(n) digits "0".
%C The number of digits of a(n) is equal to A000043(n) and also equal to the number of digits of n-th Mersenne prime written in base 2 (see A117293, A135650).
%e a(3)=10000 because the 3rd even superperfect number A061652(3)=16 and 16 written in base 2 is equal to 10000.
%Y Cf. A000043, A000668, A019279, A061652, A090748, A117293, A135650.
%K base,nonn
%O 1,1
%A _Omar E. Pol_, Feb 23 2008