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A034767 Dirichlet convolution of phi(n) with Bell numbers. 0
1, 2, 4, 8, 19, 58, 209, 888, 4150, 21170, 115985, 678642, 4213609, 27644652, 190899368, 1382959444, 10480142163, 82864874064, 682076806177, 5832742226266, 51724158235802, 474869816272746, 4506715738447345 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
From Richard L. Ollerton, May 06 2021: (Start)
a(n) = Sum_{d|n} phi(d)*A000110(n/d) (by definition).
a(n) = Sum_{k=1..n} A000110(gcd(n,k)).
a(n) = Sum_{k=1..n} A000110(n/gcd(n,k))*phi(gcd(n,k))/phi(n/gcd(n,k)). (End)
MATHEMATICA
Table[Sum[BellB[n/d - 1]*EulerPhi[d], {d, Divisors[n]}], {n, 1, 25}] (* Vaclav Kotesovec, Sep 10 2019 *)
CROSSREFS
Sequence in context: A128816 A006897 A287025 * A005518 A326997 A014225
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified April 14 20:39 EDT 2024. Contains 371667 sequences. (Running on oeis4.)