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A257099 From third root of the inverse of Riemann zeta function: form Dirichlet series Sum b(n)/n^x whose cube is 1/zeta; sequence gives numerator of b(n). 4
1, -1, -1, -1, -1, 1, -1, -5, -1, 1, -1, 1, -1, 1, 1, -10, -1, 1, -1, 1, 1, 1, -1, 5, -1, 1, -5, 1, -1, -1, -1, -22, 1, 1, 1, 1, -1, 1, 1, 5, -1, -1, -1, 1, 1, 1, -1, 10, -1, 1, 1, 1, -1, 5, 1, 5, 1, 1, -1, -1, -1, 1, 1, -154, 1, -1, -1, 1, 1, -1, -1, 5, -1, 1, 1, 1, 1, -1, -1, 10, -10, 1, -1, -1, 1, 1, 1, 5, -1, -1, 1, 1, 1, 1, 1, 22, -1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,8

COMMENTS

Dirichlet g.f. of b(n) = a(n)/A256689(n) is (zeta (x))^(-1/3).

Denominator is the same as for Dirichlet g.f. (zeta(x))^(+1/3).

Formula holds for general Dirichlet g.f. zeta(x)^(-1/k) with k = 1, 2, ...

LINKS

Wolfgang Hintze, Table of n, a(n) for n = 1..500

FORMULA

with k = 3;

zeta(x)^(-1/k) = Sum_{n>=1} b(n)/n^x;

c(1,n)=b(n); c(k,n) = Sum_{d|n} c(1,d)*c(k-1,n/d), k>1;

Then solve c(k,n) = mu(n) for b(m);

a(n) = numerator(b(n)).

MATHEMATICA

k = 3;

c[1, n_] = b[n];

c[k_, n_] := DivisorSum[n, c[1, #1]*c[k - 1, n/#1] & ]

nn = 100; eqs = Table[c[k, n]´éŐMoebiusMu[n], {n, 1, nn}];

sol = Solve[Join[{b[1] == 1}, eqs], Table[b[i], {i, 1, nn}], Reals];

t = Table[b[n], {n, 1, nn}] /. sol[[1]];

num = Numerator[t] (* A257099 *)

den = Denominator[t] (* A256689 *)

CROSSREFS

Cf. family zeta^(-1/k): A257098/A046644 (k=2), A257099/A256689 (k=3), A257100/A256691 (k=4), A257101/A256693 (k=5).

Cf. family zeta^(+1/k): A046643/A046644 (k=2), A256688/A256689 (k=3), A256690/A256691 (k=4), A256692/A256693 (k=5).

Sequence in context: A295554 A319099 A098087 * A291578 A165485 A179947

Adjacent sequences:  A257096 A257097 A257098 * A257100 A257101 A257102

KEYWORD

sign

AUTHOR

Wolfgang Hintze, Apr 16 2015

STATUS

approved

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Last modified January 18 06:34 EST 2019. Contains 319269 sequences. (Running on oeis4.)