login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157850 Numbers k such that are harmonic means of divisors of harmonic (Ore) numbers (harmonic numbers is A001599) and equal to one of the divisors of this harmonic numbers. 1

%I #9 Jul 09 2019 11:57:28

%S 1,2,5,6,8,9,11,10,15,15,14,17,24,24,21,13,19,27,25,29,26,44,44,29,46,

%T 39,46,42,47,47,35,41,60,51,37,48,45,49,50,49,53,77,86,86,51,96,75,70,

%U 80,99,110,81,84,102,82,96,114,53,108,115,105,116,91,85,105

%N Numbers k such that are harmonic means of divisors of harmonic (Ore) numbers (harmonic numbers is A001599) and equal to one of the divisors of this harmonic numbers.

%H Amiram Eldar, <a href="/A157850/b157850.txt">Table of n, a(n) for n = 1..847</a> (Calculated from the b-file at A007340)

%F a(n) = f(A007340(n)), where f(k) = k * tau(k)/sigma(k) = k * A000005(k)/A000203(k).

%e a(3) = 5, because 5 is harmonic mean of divisors of A007340(3)=140 and also is divisor of 140.

%Y Cf. A007340, A000005, A000203, A001599.

%K nonn

%O 1,2

%A _Jaroslav Krizek_, Mar 07 2009, Apr 12 2009

%E More terms from _Amiram Eldar_, Jul 09 2019

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 10 04:15 EDT 2024. Contains 375773 sequences. (Running on oeis4.)