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A369601
Dirichlet convolution of totient function with reduced totient function.
0
1, 2, 4, 5, 8, 8, 12, 10, 16, 16, 20, 18, 24, 24, 28, 22, 32, 32, 36, 36, 42, 40, 44, 36, 56, 48, 60, 54, 56, 56, 60, 48, 70, 64, 84, 70, 72, 72, 84, 72, 80, 84, 84, 90, 108, 88, 92, 78, 120, 112, 112, 108, 104, 120, 140, 108
OFFSET
1,2
FORMULA
a(n) = Sum_{d|n} A000010(d) * A002322(n/d).
EXAMPLE
a(4) = phi(1)*lambda(4) + phi(2)*lambda(2) + phi(4)*lambda(1) = 5, where lambda is Carmichael's reduced totient function.
MATHEMATICA
a[n_]:=Sum[EulerPhi[d]CarmichaelLambda[n/d], {d, Divisors[n]}]; Array[a, 56] (* Stefano Spezia, Jan 27 2024 *)
PROG
(PARI) a(n) = sumdiv(n, d, eulerphi(d)*lcm(znstar(n/d)[2]))
CROSSREFS
Sequence in context: A036694 A085624 A331376 * A345426 A061884 A286002
KEYWORD
nonn,easy
AUTHOR
Miles Englezou, Jan 26 2024
STATUS
approved