%I #12 Jul 24 2015 04:53:15
%S 0,8,117,1340,14211,146078,1480437,14902280,149511591,1497558338,
%T 14987792457,149938963820,1499694822171,14998474116998,
%U 149992370597277,1499961853010960,14999809265103951,149999046325618058,1499995231628286897
%N Sum of aliquot factors (divisors excluding the number itself) of 10^n.
%F a(n) = A001065(10^n). - _Michel Marcus_, Jul 24 2015
%F a(n) = (2^(n+1)-1)*(5^(n+1)-1)/4 - 10^n. - _Giovanni Resta_, Jul 24 2015
%e The aliquot factors of 10^1 are 1, 2 and 5; 10 is not counted, so 1 + 2 + 5 = 8.
%t Table[DivisorSum[x = 10^n, # &, # != x &], {n, 0, 18}] (* _Jayanta Basu_, Jun 30 2013 *)
%o (PARI) vector(20, n, n--; sigma(10^n) - 10^n) \\ _Michel Marcus_, Jul 24 2015
%Y Cf. A001065.
%K easy,nonn
%O 0,2
%A _Enoch Haga_
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