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A note on Ramanujan's arithmetical function τ(n)

Published online by Cambridge University Press:  24 October 2008

J. R. Wilton
Affiliation:
Trinity College

Extract

The function τ (n), defined by the equation

is considered by Ramanujan* in his memoir “On certain arithmetical functions”

The associated Diriċhlet series

converges when σ = > σ0, for a sufficiently large positive σ0.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1929

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References

* Trans. Camb. Phil. Soc. 22 (1916), 159184 (Collected papers, No. 18).Google Scholar

Proc. Camb. Phil. Soc. 19 (1920), 117124 (communicated 1917).Google Scholar

Collected papers, 153–154.Google Scholar

§ Hardy, G. H., “Note on Ramanujan's arithmetical function τ(n)”, Proc. Camb. Phil. Soc. 23 (1927), 675680.CrossRefGoogle Scholar

* Wigert, S., “Sur quelques functions arithmétiques”, Acta Math. 37 (1914), 113140 (§ 4).CrossRefGoogle Scholar

Comptes Rendus, 04 1914, 1012–4.Google Scholar

Acta Math. 37 (1914), 193238 (226).CrossRefGoogle Scholar

* Compare Hardy, G. H. and Ramanujan, S., “Asymptotic formulae in combinatory analysis”, Proc. London Math. Soc. (2), 17 (1918), 75115, Lemma 4·31. (Ramanujan's Collected Papers, No. 36.)CrossRefGoogle Scholar

Proc. Camb. Phil. Soc. 23 (1927), 675680, Lemma 1.CrossRefGoogle Scholar

* Watson, G. N., Theory of Bessel functions (1922), 177 (8). It is at this stage that the proof follows the classical method of Wigert (loc. cit.).Google Scholar

* See, for example, Hobson, E. W., Theory of functions of a real variable, 2 (1926), 288289.Google Scholar

Whittaker, and Watson, , Modern analysis (1920), 246.Google Scholar

Bromwich, , Theory of infinite series (1908), 453, Theorem B.Google Scholar

§ Since , it follows that (4·1) is absolutely and uniformly convergent if .Google Scholar

* Comptes Rendus, 178 (1924), 303.Google ScholarHobson, , loc. cit., 626.Google Scholar

(P, q) denotes the greatest common factor of p and q.Google Scholar

The change of order follows from Lemma 3 and the theorem quoted from Hobson, as in (3.61). If σ>7, Lemma 2 and the absolute convergence test are sufficient.7,+Lemma+2+and+the+absolute+convergence+test+are+sufficient.>Google Scholar