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A109727 Number of admirable numbers < 10^n. 0

%I

%S 0,13,65,379,2549,19480,159001,1345929,11676912,103136395

%N Number of admirable numbers < 10^n.

%t fQ[n_] := Block[{d = Most[Divisors[n]], k = 1}, l = Length[d]; s = Plus @@ d; While[k < l && s - 2d[[k]] > n, k++ ]; If[k > l || s != n + 2d[[k]], False, True]]; c = 0; k = 1; Do[ While[k <= 10^n, If[ fQ[k], c++ ]; k++ ]; k++; Print[c], {n, 7}] (* _Robert G. Wilson v_ *)

%Y Cf. A111592.

%K nonn

%O 1,2

%A _Jason Earls_, Aug 10 2005

%E a(7) from _Robert G. Wilson v_, Aug 13 2005

%E a(8)-a(10) from _Donovan Johnson_, Jan 25 2012

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Last modified October 19 21:28 EDT 2019. Contains 328244 sequences. (Running on oeis4.)