×

Are the hyperharmonics integral? A partial answer via the small intervals containing primes. (English) Zbl 1226.11031

Let \(H_n:=1+\frac 12+\ldots+\frac 1n \) be the harmonic numbers. For a positive integer \(r\) the hyperharmonic numbers of order \(r\) are defined by \[ H_n^{(1)}:=H_n,H_n^{(r)}= \sum_{k=1}^nH_k^{(r-1)}, r>1. \] The authors prove: For any \(s\in(1,2)\) there is a prime number \(P_0\) such that for any integers \(r\) and \(n\) with \(5\leq r\leq (2-s)P_0+2\) and \(n\geq P_0\) the number \(H_n^{(r)}\) is not an integer. The number \(H_n^{(r)}\) is not an integer for \(n\geq 2\) and \(5\leq r\leq 25\), for \(n\geq 2.010.881\) and \(5\leq r\leq 2.010.761\), for \(n\geq 10.726.905.041\) and \(5\leq r\leq 10.726.904.664\).

MSC:

11B83 Special sequences and polynomials

References:

[1] Aït Amrane, R.; Belbachir, H., Non-integerness of class of hyperharmonic numbers, Ann. Mathematicae et Informaticae, 37, 7-11 (2010) · Zbl 1224.11033
[2] Bazzanella, D.; Languasco, A.; Zaccagnini, A., Prime numbers in logarithmic intervals (17 Sept. 2008)
[3] Conway, J. H.; Guy, R. K., The Book of Numbers (1996), Springer-Verlag: Springer-Verlag New York · Zbl 0866.00001
[4] Giordano, G., The generalization and proof of Bertrand’s Postulate, Internat. J. Math. & Math. Sci., 10, 4, 821-824 (1987) · Zbl 0625.10005
[5] Jia, C., Almost all short intervals containing prime numbers, Acta Arith., LXXVLI (1996) · Zbl 0841.11043
[6] Jitsuro, N., On the interval containing at least one prime number, Proc. Japan Acad., 28, 177-181 (1952) · Zbl 0047.04405
[7] Mező, I., About the non-integer property of hyperharmonic numbers, Ann. Univ. Sci. Budapest, Sect. Math., 50, 13-20 (2007) · Zbl 1212.11035
[8] Ramaré, O.; Saouter, Y., Short effective intervals containing primes, J. Number Theory, 98, 10-33 (2003) · Zbl 1032.11038
[9] Schoenfeld, L., Sharper bounds for the Chebyshev functions \(\theta(x)\) and \(\psi(x)\). II, Math. Comp., 30, 134, 337-360 (1976) · Zbl 0326.10037
[10] Taeisinger, L., Bemerkung über die harmonische Reihe, Monatsch. Math. Phys., 26, 132-134 (1915) · JFM 45.0419.01
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.