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 A271102 a(n) is multiplicative with a(p^e) = -1 if e=2, a(p^e) = 0 if e=1 or e>2. 9
 1, 0, 0, -1, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA Dirichlet g.f.: 1 / zeta(2*s). abs(a(n)) = A227291(n). Moebius transform of A008966. A008966(n) = abs(mu(n)) = Sum_{d|n} a(d), where mu is the Moebius function (A008683). - Michael Somos, Jan 30 2020 EXAMPLE G.f. = x - x^4 - x^9 - x^25 + x^36 - x^49 + x^100 - x^121 - x^169 + ... MATHEMATICA Table[Times @@ Apply[Times, FactorInteger[n] /. {p_, e_} /; p > 1 :> If[e == 2, -1, 0]], {n, 105}] (* Michael De Vlieger, Jul 29 2017 *) Table[DivisorSum[n, Abs[MoebiusMu[#]]*MoebiusMu[n/#] &], {n, 1, 100}] (* Vaclav Kotesovec, Apr 08 2019 *) PROG (PARI) {a(n) = if( n<1, 0, direuler( p=2, n, 1 - X^2 )[n])}; (PARI) {a(n) = my(A, p, e); if( n<1, 0, A = factor(n); prod(k=1, matsize(A)[1], [p, e] = A[k, ]; -(e==2)))}; (Scheme) (define (A271102 n) (if (= 1 n) n (* (if (= 2 (A067029 n)) -1 0) (A271102 (A028234 n))))) ;; Antti Karttunen, Jul 28 2017 CROSSREFS Cf. A008966, A227291 (gives the absolute values), Dirichlet inverse of A010052. Sequence in context: A014504 A014999 A227291 * A326072 A304362 A330682 Adjacent sequences:  A271099 A271100 A271101 * A271103 A271104 A271105 KEYWORD sign,mult AUTHOR Michael Somos, Mar 30 2016 EXTENSIONS More terms from Antti Karttunen, Jul 28 2017 STATUS approved

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Last modified November 23 14:26 EST 2020. Contains 338590 sequences. (Running on oeis4.)