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%I #8 Nov 03 2019 06:47:12
%S 4,5,16,21,31,41,92,156,91,216,121,185,336,640,249,316,608,459,241,
%T 596,476,704,1296,493,627,619,1340,521,541,1072,1647,691,1416,859,
%U 1281,1624,1916,1445,1257,1696,4800,1301,1509,1363,1313,2804,2192,2200,1427
%N Arithmetic derivative of the average of n-th twin prime pair.
%H Amiram Eldar, <a href="/A078581/b078581.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A003415(A014574(n)).
%t midQ[n_] := PrimeQ[n-1] && PrimeQ[n+1]; f[n_] := n * Total[#2 / #1 & @@@ FactorInteger[n]]; f /@ Select[Range[1500], midQ] (* _Amiram Eldar_, Nov 03 2019 *)
%Y Cf. A003415, A014574, A078579.
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, Nov 29 2002
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