|
%I #18 Mar 30 2023 02:31:08
%S 3,3,11,5,37,7,5,11,521,47,71,79,547,911,32783,241,307,6899,24967,
%T 87383,457,4799,270601,7109,3728273,12497,1201,100613,2017,17318417,
%U 859,87211,47491,8589934609,195329,1483453,320370521,8191129,549755813927,478881371
%N Greatest prime dividing 2^n + n.
%H Amiram Eldar, <a href="/A359685/b359685.txt">Table of n, a(n) for n = 1..406</a>
%F a(n) = A006530(A006127(n)).
%p a:= n-> max(numtheory[factorset](2^n+n)):
%p seq(a(n), n=1..40); # _Alois P. Heinz_, Jan 11 2023
%t a[n_] := FactorInteger[2^n + n][[-1, 1]]; Array[a, 40] (* _Amiram Eldar_, Mar 30 2023 *)
%o (PARI) a(n) = vecmax(factor(2^n+n)[,1]); \\ _Michel Marcus_, Jan 11 2023
%o (Python)
%o from sympy import primefactors
%o def A359685(n): return max(primefactors((1<<n)+n)) # _Chai Wah Wu_, Jan 11 2023
%Y Cf. A000040, A006127, A006530.
%K nonn
%O 1,1
%A _Philippe Deléham_, Jan 11 2023
|
