OFFSET
1,2
MATHEMATICA
Table[DirichletConvolve[DivisorSigma[1, k], CarmichaelLambda[k], k, n], {n, 1, 100}] (* Amiram Eldar, Sep 15 2023 *)
PROG
(Python)
from sympy import divisors, reduced_totient, divisor_sigma
def a(n): return sum(divisor_sigma(d, 1) * reduced_totient(n//d) for d in divisors(n))
CROSSREFS
KEYWORD
nonn
AUTHOR
Torlach Rush, Sep 14 2023
STATUS
approved