A023591 Greatest exponent in prime-power factorization of 2*prime(n)+1.

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, 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, 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

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Crossrefs

Cf. A051903, A072055.

Programs

Maple

A023591 := proc(n)
    A051903(2*ithprime(n)+1) ;
end proc: # R. J. Mathar, Jul 08 2015

Mathematica

a[n_] := Max[FactorInteger[2*Prime[n] + 1][[;;, 2]]]; Array[a, 100] (* Amiram Eldar, Sep 09 2024 *)

PARI

a(n) = vecmax(factor(2*prime(n)+1)[,2]); \\ Michel Marcus, Apr 20 2021

Formula

a(n) = A051903(A072055(n)). - Amiram Eldar, Sep 09 2024