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 A348709 Number of squarefree integers with an even number of prime factors <= 10^n. 1
 1, 3, 31, 305, 3030, 30373, 304069, 3040164, 30397311, 303963451, 3039618610, 30396311212, 303963582320, 3039635808938, 30396354655186, 303963549318865, 3039635507672484, 30396355081786770, 303963550903632005, 3039635509720135531, 30396355092931863204, 303963550925315375170 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS a(n) is the number of integers k <= 10^n with mu(k)=1 where mu(k) is the Möbius function. LINKS FORMULA a(n) = (A071172(n) + A084237(n)) / 2. Lim_{n->oo} a(n)/10^n = 3/Pi^2 (A104141). EXAMPLE a(1) = 3 because there are 3 squarefree integers with an even number of prime factors <= 10: 1, 6, 10. MATHEMATICA Table[Length@Select[Range[10^n], MoebiusMu@#==1&], {n, 0, 6}] CROSSREFS Cf. A071172, A084237, A008683, A030229, A104141, A348708. Sequence in context: A236957 A112425 A144579 * A220997 A222094 A069589 Adjacent sequences: A348706 A348707 A348708 * A348710 A348711 A348712 KEYWORD nonn AUTHOR Giorgos Kalogeropoulos, Oct 30 2021 STATUS approved

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Last modified March 25 00:24 EDT 2023. Contains 361511 sequences. (Running on oeis4.)