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A003972 Moebius transform of A003961. 4
1, 2, 4, 6, 6, 8, 10, 18, 20, 12, 12, 24, 16, 20, 24, 54, 18, 40, 22, 36, 40, 24, 28, 72, 42, 32, 100, 60, 30, 48, 36, 162, 48, 36, 60, 120, 40, 44, 64, 108, 42, 80, 46, 72, 120, 56, 52, 216, 110, 84, 72, 96, 58, 200, 72, 180, 88, 60, 60, 144, 66, 72, 200, 486, 96, 96, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

Multiplicative with a(p^e) = (q-1)q^(e-1) where q = nextPrime(p). - David W. Wilson, Sep 01 2001

MATHEMATICA

b[1] = 1; b[p_?PrimeQ] := b[p] = Prime[ PrimePi[p] + 1]; b[n_] := b[n] = Times @@ (b[First[#]]^Last[#] &) /@ FactorInteger[n]; a[n_] := Sum[ MoebiusMu[n/d]*b[d], {d, Divisors[n]}]; Table[a[n], {n, 1, 70}]  (* Jean-François Alcover, Jul 18 2013 *)

CROSSREFS

Sequence in context: A099188 A085271 A260812 * A023853 A056526 A049066

Adjacent sequences:  A003969 A003970 A003971 * A003973 A003974 A003975

KEYWORD

nonn,mult

AUTHOR

Marc LeBrun

EXTENSIONS

More terms from David W. Wilson, Aug 29 2001

STATUS

approved

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Last modified May 30 05:08 EDT 2020. Contains 334712 sequences. (Running on oeis4.)