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Dirichlet convolution of sigma with reduced totient function.
2

%I #12 Sep 20 2023 15:59:47

%S 1,4,6,12,10,24,14,30,27,40,22,70,26,56,56,70,34,108,38,116,78,88,46,

%T 172,75,104,108,162,58,224,62,158,122,136,128,310,74,152,144,284,82,

%U 312,86,254,242,184,94,396,147,300,188,300,106,432,200,396,210,232,118

%N Dirichlet convolution of sigma with reduced totient function.

%F a(n) = Sum{d|n} A000203(d) * A002322(n/d).

%F a(p) = A365647(p) where p is a term of A000040.

%t Table[DirichletConvolve[DivisorSigma[1, k], CarmichaelLambda[k], k, n], {n, 1, 100}] (* _Amiram Eldar_, Sep 15 2023 *)

%o (Python)

%o from sympy import divisors, reduced_totient, divisor_sigma

%o def a(n): return sum(divisor_sigma(d, 1) * reduced_totient(n//d) for d in divisors(n))

%Y Cf. A000040, A000203, A002322, A365647.

%K nonn

%O 1,2

%A _Torlach Rush_, Sep 14 2023