A229271 - OEIS

%I #9 Sep 18 2013 12:40:26

%S 10,14,15,21,26,33,35,38,51,65,66,78,86,93,102,110,111,123,161,201,

%T 203,206,209,215,221,230,258,278,282,321,371,374,395,398,402,413,438,

%U 470,471,485,530,533,543,545,551,590,626,671,678,698,723,755,779,803,815

%N Numbers n for which n + n' and n - n' are both prime, n' being the arithmetic derivative of n.

%C Intersection of A165561 and A229269.

%H Paolo P. Lava, <a href="/A229271/b229271.txt">Table of n, a(n) for n = 1..1000</a>

%p with(numtheory); P:=proc(q) local a,n,p; for n from 1 to q do

%p a:=n*add(op(2,p)/op(1,p),p=ifactors(n)[2]);

%p if isprime(n+a) and isprime(n-a) then print(n); fi;

%p od; end: P(10^5);

%Y Cf. A003415, A165561, A165562, A229269, A229270, A229272.

%K nonn

%O 1,1

%A _Paolo P. Lava_, Sep 18 2013