%I A138816
%S A138816 326,742,314,168,843,168,521,212,212,631,181,181
%N A138816 Concatenation of initial digit of n-th Mersenne prime A000668(n), initial 
               digit of n-th even superperfect number A061652(n) and initial digit 
               of n-th perfect number A000396(n).
%C A138816 Also, concatenation of initial digit of n-th Mersenne prime A000668(n), 
               initial digit of n-th superperfect number A019279(n) and initial 
               digit of n-th perfect number A000396(n), if there are no odd superperfect 
               numbers.
%C A138816 Also, concatenation of A135613(n), A138124(n) and A135617(n).
%H A138816 L. C. Noll, <a href="http://www.isthe.com/chongo/tech/math/prime/mersenne.html">
               Mersenne Prime Digits and Names</a>.
%H A138816 O. E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica 
               de los numeros primos y perfectos</a>.
%Y A138816 Cf. A000396, A000668, A019279, A061652, A135613, A135167, A138124, A138817.
%Y A138816 Sequence in context: A048918 A031516 A066128 this_sequence A138817 A158271 
               A097737
%Y A138816 Adjacent sequences: A138813 A138814 A138815 this_sequence A138817 A138818 
               A138819
%K A138816 base,more,nonn
%O A138816 1,1
%A A138816 Omar E. Pol (info(AT)polprimos.com), Apr 01 2008