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%I #12 Sep 09 2024 02:40:46
%S 1,1,1,1,1,3,1,1,1,1,2,2,1,1,1,1,1,1,3,1,2,1,1,1,1,1,2,1,1,1,1,1,2,2,
%T 1,1,2,1,1,1,1,2,1,2,1,1,2,1,1,3,1,1,1,1,1,1,2,1,1,1,4,1,1,1,1,1,1,3,
%U 1,1,1,1,2,2,1,1,1,1,1,2,1,1,1,2,1,1,1,1,1,2,1,1,2,1,3,1,1,1,1
%N Greatest exponent in prime-power factorization of 2*prime(n)+1.
%F a(n) = A051903(A072055(n)). - _Amiram Eldar_, Sep 09 2024
%p A023591 := proc(n)
%p A051903(2*ithprime(n)+1) ;
%p end proc: # _R. J. Mathar_, Jul 08 2015
%t a[n_] := Max[FactorInteger[2*Prime[n] + 1][[;;, 2]]]; Array[a, 100] (* _Amiram Eldar_, Sep 09 2024 *)
%o (PARI) a(n) = vecmax(factor(2*prime(n)+1)[,2]); \\ _Michel Marcus_, Apr 20 2021
%Y Cf. A051903, A072055.
%K nonn
%O 1,6
%A _Clark Kimberling_