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A143519 Moebius transform of A010051, the characteristic function of the primes: a(n) = Sum_{d|n} mu(n/d)*A010051(d); A054525 * A010051. 6
0, 1, 1, -1, 1, -2, 1, 0, -1, -2, 1, 1, 1, -2, -2, 0, 1, 1, 1, 1, -2, -2, 1, 0, -1, -2, 0, 1, 1, 3, 1, 0, -2, -2, -2, 0, 1, -2, -2, 0, 1, 3, 1, 1, 1, -2, 1, 0, -1, 1, -2, 1, 1, 0, -2, 0, -2, -2, 1, -1, 1, -2, 1, 0, -2, 3, 1, 1, -2, 3, 1, 0, 1, -2, 1, 1, -2, 3, 1, 0, 0, -2, 1, -1, -2, -2, -2, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

A010051 = A051731 * A143519 (since A051731 = the inverse Mobius transform).

A000720(n) = Sum_{k=1..n} a(k) floor(n/k) where A000720(n) is the number of primes <= n. - Steven Foster Clark, May 25 2018

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

Mobius transform of A010051, the characteristic function of the primes.

Row sums of triangle A143518.

a(n) = Sum_{d|n} A010051(d)*A008683(n/d). - Antti Karttunen, Jul 19 2017

EXAMPLE

a(4) = -1 since row 4 of triangle A043518 = (0, -1, 0, 0).

a(4) = -1 = (0, -1, 0, 1) dot (0, 1, 1, 0), where (0, -1, 0, 1) = row 4 of A054525 and A010051 = (0, 1, 1, 0, 1, 0, 1, 0, ...).

MATHEMATICA

Table[Sum[MoebiusMu[n/d] Boole[PrimeQ@ d], {d, Divisors@ n}], {n, 89}] (* Michael De Vlieger, Jul 19 2017 *)

PROG

(Sage)

def A143519(n) :

    D = filter(is_prime, divisors(n))

    return add(moebius(n/d) for d in D)

[A143519(n) for n in (1..89)]   # Peter Luschny, Feb 01 2012

(PARI) A143519(n) = sumdiv(n, d, isprime(d)*moebius(n/d)); \\ (After Luschny's Sage-code) - Antti Karttunen, Jul 19 2017

CROSSREFS

Cf. A008683, A010051, A143518, A054525, A137851.

Sequence in context: A203827 A194289 A237194 * A029376 A276790 A029359

Adjacent sequences:  A143516 A143517 A143518 * A143520 A143521 A143522

KEYWORD

sign

AUTHOR

Gary W. Adamson, Aug 22 2008

EXTENSIONS

More terms from R. J. Mathar, Jan 19 2009

STATUS

approved

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Last modified July 18 21:23 EDT 2018. Contains 312765 sequences. (Running on oeis4.)