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A083348 Numbers k such that r(k) = Sum(e/p: k = Product(p^e)) > 1. 8

%I #39 Feb 23 2024 07:27:28

%S 8,12,16,18,20,24,28,30,32,36,40,44,48,52,54,56,60,64,68,72,76,80,81,

%T 84,88,90,92,96,100,104,108,112,116,120,124,126,128,132,135,136,140,

%U 144,148,150,152,156,160,162,164,168,172,176,180,184,188,189,192,196,198

%N Numbers k such that r(k) = Sum(e/p: k = Product(p^e)) > 1.

%C The number of terms not exceeding 10^m, for m = 1, 2, ..., are 1, 29, 318, 3174, 31763, 317813, 3177179, 31774009, 317745099, 3177373819, ... . Apparently, the asymptotic density of this sequence exists and equals 0.3177... . - _Amiram Eldar_, Jun 24 2022

%H T. D. Noe, <a href="/A083348/b083348.txt">Table of n, a(n) for n = 1..1000</a>

%F A083345(a(n)) > A083346(a(n)).

%F A083345(A051674(n)) = A083346(A051674(n)).

%F A083345(A083347(n)) < A083346(A083347(n)).

%F A168036(a(n)) > 0. - _Reinhard Zumkeller_, May 22 2015

%t ad[n_] := Switch[n, 0 | 1, 0, _, If[PrimeQ[n], 1, Sum[Module[ {p, e}, {p, e} = pe; n e/p], {pe, FactorInteger[n]}]]];

%t Select[Range[1000], ad[#] > # &] (* _Jean-François Alcover_, May 04 2023 *)

%o (Haskell)

%o a083348 n = a083348_list !! (n-1)

%o a083348_list = filter ((> 0) . a168036) [1..]

%o -- _Reinhard Zumkeller_, May 22 2015, May 10 2011

%Y Cf. A003415, A072873, A051674, A083345, A083346, A083347, A168036, A369048 (characteristic function), A369049.

%Y Subsequence of A100717.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Apr 25 2003

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Last modified April 25 10:01 EDT 2024. Contains 371967 sequences. (Running on oeis4.)