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A046914
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Sum of aliquot factors (divisors excluding the number itself) of 10^n.
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0
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0, 8, 117, 1340, 14211, 146078, 1480437, 14902280, 149511591, 1497558338, 14987792457, 149938963820, 1499694822171, 14998474116998, 149992370597277, 1499961853010960, 14999809265103951, 149999046325618058, 1499995231628286897
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (2^(n+1)-1)*(5^(n+1)-1)/4 - 10^n. - Giovanni Resta, Jul 24 2015
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EXAMPLE
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The aliquot factors of 10^1 are 1, 2 and 5; 10 is not counted, so 1 + 2 + 5 = 8.
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MATHEMATICA
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Table[DivisorSum[x = 10^n, # &, # != x &], {n, 0, 18}] (* Jayanta Basu, Jun 30 2013 *)
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PROG
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(PARI) vector(20, n, n--; sigma(10^n) - 10^n) \\ Michel Marcus, Jul 24 2015
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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