

A076637


Numerators of harmonic numbers when these numerators are divisible by squares of primes >= 5 in the case of Wolstenholme's Theorem.


3



25, 49, 7381, 86021, 2436559, 14274301, 19093197, 315404588903, 9304682830147, 54801925434709, 2078178381193813, 12309312989335019, 5943339269060627227, 14063600165435720745359, 254381445831833111660789, 15117092380124150817026911
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OFFSET

1,1


COMMENTS

By Wolstenholme's Theorem, if p prime >= 5, the numerator of the harmonic number H_{p1} is always divisible by p^2. The obtained quotients are in A061002.  Bernard Schott, Dec 02 2018
The numbers 363, numerator of H_7 and 9227046511387, numerator of H_{29}, which have been found by Amiram Eldar and Michel Marcus, are also divisible by prime squares, respectively by 11^2 and 43^2, but not in the case of Wolstenholme's Theorem. So, a new sequence A322434 is created with all the numerators of Harmonic numbers which are divisible by any prime square >= 5.  Bernard Schott, Dec 08 2018


LINKS

Table of n, a(n) for n=1..16.
Eric Weisstein's World of Mathematics, Wolstenholme's Theorem


EXAMPLE

25 is a term because the numerator of the harmonic number H_4 = 1 + 1/2+ 1/3 + 1/4 = 25/12 is divisible by the square of 5;
49 is a term because the numerator of the harmonic number H_6 = 1 + 1/2+ 1/3 + 1/4 + 1/5 + 1/6 = 49/20 is divisible by the square of 7.


MATHEMATICA

a[p_] := Numerator[HarmonicNumber[p  1]]; a /@ Prime@Range[3, 20] (* Amiram Eldar, Dec 08 2018 *)


CROSSREFS

Cf. A076638, A001008.
Sequence in context: A056981 A132585 A049228 * A040600 A277190 A236849
Adjacent sequences: A076634 A076635 A076636 * A076638 A076639 A076640


KEYWORD

nonn,frac


AUTHOR

Michael Gilleland (megilleland(AT)yahoo.com), Oct 23 2002


EXTENSIONS

More terms from Amiram Eldar, Dec 04 2018


STATUS

approved



