A375568 - OEIS

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A375568

a(n) = denominator(A006571(n)/A366450(n)) if A366450(n) != 0, otherwise 1.

1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 2, 1, 1, 1, 4, 1, 3, 1, 2, 1, 1, 1, 1, 5, 1, 9, 2, 1, 1, 1, 4, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 4, 14, 5, 1, 2, 1, 9, 1, 1, 1, 1, 1, 2, 1, 1, 3, 8, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 4, 27, 1, 1, 2, 1, 1, 1, 1, 1, 3, 1, 2, 1, 1, 1, 4, 1, 14, 3, 5, 1, 1, 1, 1

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OFFSET

1,4

COMMENTS

a(n) differs from A071974 at n = 27, 32, 36, 49, 54, 72, 76, 81, 96, 98, 100, 108, 116, 125, 135, 144,...

a(n) differs from A056622 at n = 27, 32, 36, 49, 54, 72, 76, 81, 96, 98, 100, 108, 116, 125, 128, 135, 144,...

GCD(a(n), A071974(n)) differs from A071974 at n = 36, 72, 76, 100, 116, 144,...

GCD(a(n), A056622(n)) differs from A056622 at n = 36, 72, 76, 100, 116, 128, 144,...

LINKS

Table of n, a(n) for n=1..104.

MATHEMATICA

nn = 104; a[n_] := DivisorSum[n, MoebiusMu[#] # &]; f = (x^3 - x^2 - y^2 - y); w[n_] := SeriesCoefficient[q*(Product[(1 - q^k), {k, 11, n, 11}]*Product[1 - q^k, {k, n}])^2, {q, 0, n}]; A006571 = ParallelTable[w[n], {n, 1, nn}]; A366450 = ParallelTable[Sum[Sum[Sum[If[GCD[f, n] == k, 1, 0]*a[k]/n, {x, 1, n}], {y, 1, n}], {k, 1, n}], {n, 1, nn}]; Denominator[A006571/A366450]

CROSSREFS

Cf. A006571, A366450, A056622, A071974.

Sequence in context: A076933 A071974 A056622 * A331738 A372328 A306333

Adjacent sequences: A375564 A375565 A375566 * A375569 A375570 A375571

KEYWORD

nonn,frac

AUTHOR

Mats Granvik, Aug 19 2024

STATUS

approved