A078576 - OEIS

%I #12 Nov 03 2019 06:46:29

%S 2,5,5,5,10,12,10,5,22,5,28,10,10,5,16,24,10,10,52,18,34,17,5,23,34,

%T 29,10,108,112,21,10,142,28,29,12,27,48,17,64,25,5,51,76,53,43,21,29,

%U 16,37,36,72,10,144,288,53,154,18,318,35,23,42,18,352,34,16,81,29,378,12

%N Sum of distinct prime factors of the average of n-th twin prime pair.

%H Amiram Eldar, <a href="/A078576/b078576.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A008472(A014574(n)).

%e 12th twin prime pair = (A001359(12), A006512(12)) = (149,151), hence A014574(12) = 150 = 2*3*5*5, therefore a(12) = 2+3+5 = 10.

%t midQ[n_] := PrimeQ[n-1] && PrimeQ[n+1]; f[n_] := Plus @@ FactorInteger[n][[;;,1]]; f /@ Select[Range[3000], midQ] (* _Amiram Eldar_, Nov 03 2019 *)

%Y Cf. A008472, A014574, A078577, A078575, A078570.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Nov 29 2002