The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A201463 A list of 25 distinct numbers such that the sum of their reciprocals is 1 and each number is of the form p^i*q^j where p and q are distinct primes. 4

%I #29 Sep 08 2020 02:03:49

%S 6,10,12,14,15,18,21,22,24,26,28,33,35,36,39,48,52,56,65,72,88,91,99,

%T 117,144

%N A list of 25 distinct numbers such that the sum of their reciprocals is 1 and each number is of the form p^i*q^j where p and q are distinct primes.

%C At the time Burshtein's paper appeared, this was the smallest example known of this type (it may still be the smallest).

%C Incidentally, this was the 200000th sequence added to the OEIS.

%C For the smallest example (20 numbers) of this type, see A237051. - _Jon E. Schoenfield_, Feb 02 2014

%D E. J. Barbeau, Expressing one as a sum of distinct reciprocals: comments and a bibliography, Eureka (Ottawa), 3 (1977), 178-181.

%H N. Burshtein, <a href="https://doi.org/10.1016/j.disc.2005.09.017">Improving solutions of Sum_{i=1..k} 1/x_i = 1 ...</a>, Discrete Math., 306 (2006), 1438-1439.

%H <a href="/index/Ed#Egypt">Index entries for sequences related to Egyptian fractions</a>

%Y Cf. A201464, A201514, A201650.

%K nonn,fini,full

%O 1,1

%A _N. J. A. Sloane_, Dec 01 2011

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 June 7 08:44 EDT 2024. Contains 373160 sequences. (Running on oeis4.)