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A020482 Greatest p with p, q both prime, p+q = 2n.

%I A020482 #23 Nov 19 2024 17:23:32
%S A020482 2,3,5,7,7,11,13,13,17,19,19,23,23,23,29,31,31,31,37,37,41,43,43,47,
%T A020482 47,47,53,53,53,59,61,61,61,67,67,71,73,73,73,79,79,83,83,83,89,89,89,
%U A020482 79,97,97,101,103,103,107,109,109,113,113,113,109,113,113,109,127,127,131,131
%N A020482 Greatest p with p, q both prime, p+q = 2n.
%C A020482 a(n) = A171637(n,A035026(n)). - _Reinhard Zumkeller_, Mar 03 2014
%H A020482 H. J. Smith, <a href="/A020482/b020482.txt">Table of n, a(n) for n = 2..20000</a>
%t A020482 a[n_] := {p, q} /. {ToRules @ Reduce[p+q == 2*n, {p, q}, Primes]} // Max; Table[a[n], {n, 2, 100}] (* _Jean-François Alcover_, Dec 19 2013 *)
%t A020482 Table[Max[Flatten[Select[IntegerPartitions[2n,{2}],AllTrue[#,PrimeQ]&]]],{n,2,70}] (* _Harvey P. Dale_, Sep 04 2024 *)
%o A020482 (Haskell)
%o A020482 a020482 = last . a171637_row  -- _Reinhard Zumkeller_, Mar 03 2014
%o A020482 (PARI) a(n)=forprime(q=2,n,if(isprime(2*n-q), return(2*n-q))) \\ _Charles R Greathouse IV_, Apr 28 2015
%o A020482 (Python)
%o A020482 from sympy import primerange, isprime
%o A020482 def A020482(n): return next(m for p in primerange(2*n) if isprime(m:=(n<<1)-p)) # _Chai Wah Wu_, Nov 19 2024
%Y A020482 Cf. A060264, A020481.
%K A020482 nonn
%O A020482 2,1
%A A020482 _David W. Wilson_