|
%I #13 Feb 14 2018 06:12:13
%S 3,3,5,3,3,5,3,19,5,3,7,29,3,5,3,5,3,43,5,3,7,3,7,3,5,3,11,3,5,5,3,7,
%T 89,7,3,5,3,3,5,3,13,113,7,13,127,5,3,11,137,139,5,13,3,7,3,5,5,3,7,3,
%U 13,5,19,3,3,31,197,199,7,13,17,11,3,5,3,229,5,3,11,5,11,3,19,3,7,3,7
%N Values of r occurring in A063713.
%C This is not a mere union of A002373 and A020483 because of the minimality property of these sequences.
%H Robert Israel, <a href="/A063714/b063714.txt">Table of n, a(n) for n = 1..10000</a>
%p f:= proc(n) local k;
%p k:= 2;
%p while k < 2*n do
%p k:= nextprime(k);
%p if isprime(2*n+k) and isprime(2*n-k) then return k fi
%p od;
%p NULL
%p end proc:
%p map(f, [$1..400]); # _Robert Israel_, Oct 09 2017
%t f[n_] := {AnyTrue[Prime[Range[PrimePi[2n-2]]], (r = #; PrimeQ[2n+r] && PrimeQ[2n-r])&], r}; Select[f /@ Range[200], #[[1]] =!= False &][[All, 2]] (* _Jean-François Alcover_, Feb 14 2018 *)
%Y Cf. A063713, A002373, A020483.
%K nonn,look
%O 1,1
%A _Reinhard Zumkeller_, Aug 10 2001
|
