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 A342693 a(n) = Sum_{d|n} mu(d) * floor(n/d^2). 0
 1, 2, 3, 3, 5, 5, 7, 6, 8, 8, 11, 8, 13, 11, 14, 12, 17, 12, 19, 15, 19, 17, 23, 16, 24, 20, 24, 21, 29, 19, 31, 24, 30, 26, 34, 24, 37, 29, 35, 29, 41, 29, 43, 33, 39, 35, 47, 32, 48, 36, 46, 39, 53, 36, 53, 41, 51, 44, 59, 38, 61, 47, 55, 48, 63, 44, 67, 51, 62, 50, 71, 48 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For primes p, a(p) = Sum_{d|p} mu(d) * floor(p/d^2) = mu(1)*p + mu(p)*0 = p. LINKS Table of n, a(n) for n=1..72. EXAMPLE a(12) = Sum_{d|12} mu(d) * floor(12/d^2) = mu(1)*12 + mu(2)*3 + mu(3)*1 + mu(4)*0 + mu(6)*0 + mu(12)*0 = 12 - 3 - 1 + 0 + 0 + 0 = 8. MATHEMATICA Table[Sum[MoebiusMu[k] Floor[n/k^2] (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 80}] CROSSREFS Cf. A008683 (mu). Sequence in context: A325163 A348538 A185075 * A349338 A074399 A090302 Adjacent sequences: A342690 A342691 A342692 * A342694 A342695 A342696 KEYWORD nonn AUTHOR Wesley Ivan Hurt, May 18 2021 STATUS approved

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Last modified December 3 21:20 EST 2023. Contains 367540 sequences. (Running on oeis4.)