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A344525 a(n) = Sum_{1 <= x_1, x_2, ... , x_n <= n} gcd(x_1,x_2, ... ,x_n). 6
1, 5, 30, 276, 3165, 47521, 826000, 16843792, 387723045, 10009889889, 285360865350, 8918311872516, 302888304741841, 11112685595264369, 437898699063881208, 18447025862624951488, 827242515246907227633, 39346558373191515582161 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = Sum_{k=1..n} phi(k) * floor(n/k)^n.
a(n) ~ n^n. - Vaclav Kotesovec, May 23 2021
MATHEMATICA
a[n_] := Sum[EulerPhi[k] * Quotient[n, k]^n, {k, 1, n}]; Array[a, 20] (* Amiram Eldar, May 22 2021 *)
PROG
(PARI) a(n) = sum(k=1, n, eulerphi(k)*(n\k)^n);
CROSSREFS
Main diagonal of A344479.
Sequence in context: A353547 A199131 A342389 * A277464 A258300 A276752
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 22 2021
STATUS
approved

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Last modified April 16 18:02 EDT 2024. Contains 371750 sequences. (Running on oeis4.)