Published online by Cambridge University Press: 24 October 2008
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.
* Trans. Camb. Phil. Soc. 22 (1916), 159–184 (Collected papers, No. 18).Google Scholar
† Proc. Camb. Phil. Soc. 19 (1920), 117–124 (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), 675–680.CrossRefGoogle Scholar
* Wigert, S., “Sur quelques functions arithmétiques”, Acta Math. 37 (1914), 113–140 (§ 4).CrossRefGoogle Scholar
† Comptes Rendus, 04 1914, 1012–4.Google Scholar
‡ Acta Math. 37 (1914), 193–238 (226).CrossRefGoogle Scholar
* Compare Hardy, G. H. and Ramanujan, S., “Asymptotic formulae in combinatory analysis”, Proc. London Math. Soc. (2), 17 (1918), 75–115, Lemma 4·31. (Ramanujan's Collected Papers, No. 36.)CrossRefGoogle Scholar
† Proc. Camb. Phil. Soc. 23 (1927), 675–680, 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), 288–289.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