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%I #2 Mar 31 2012 20:47:17
%S 1,13,134,1347,13476,1347612,13476128,1347612815,134761281513,
%T 13476128151318,1347612815131812,134761281513181228,
%U 13476128151318122814,1347612815131812281424,134761281513181228142424
%N Concatenation of first n elements of the sigma function, where sigma(n) is the sum of divisors of n.
%Y Sigma function: A000203. Cf. A007908, A019518.
%K easy,nonn,base
%O 1,2
%A _Omar E. Pol_, Sep 05 2007