The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A273933 Amicable 5-tuples: (x1,...,x5) such that sigma(x1)=...=sigma(x5)=x1+...+x5, x1<x2<x3<x4<x5. Sequence gives x4 numbers. 7
60074174160, 71957405520, 75710489400, 96058282320, 96058282320, 97306569360, 96759542880, 94972878000, 109117562400 (list; graph; refs; listen; history; text; internal format)



The 5-tuple starting with 53542288800 was given by Donovan Johnson. The common value of sigma(x) is 294821130240.

A larger 5-tuple, (55766707476480, 56992185169920, 57515254917120, 57754372515840, 57829096765440), was found by Michel Marcus on Dec 09 2013. The common value of sigma(x) is 285857616844800.

A still larger example (227491164588441600, 228507506351308800, 229862628701798400, 230878970464665600, 243752632794316800), probably the first one to be published, had been found by Yasutoshi Kohmoto in 2008, cf. link to SeqFan post.

Other terms from John Cerkan.

There are different definitions for amicable k-tuples, cf. link to MathWorld.


Table of n, a(n) for n=1..9.

John Cerkan, More terms, with gaps.

Yasutoshi Kohmoto, Sigma(x)=Sigma(y)=Sigma(z)=Sigma(u)=Sigma(v)=x+y+z+u+v, SeqFan list, Nov 23 2008

Yasutoshi Kohmoto, Sigma(x)=Sigma(y)=Sigma(z)=Sigma(u)=Sigma(v)=x+y+z+u+v, SeqFan list, Dec 09 2013

Eric W. Weisstein, Amicable Triple. From MathWorld--A Wolfram Web Resource.


Cf. A233553, A273928, A273930, A273931, A273934, A273936 (5-tuples).

Cf. A036471 - A036474 and A116148 (quadruples).

Cf. A125490 - A125492 and A137231 (triples).

Sequence in context: A015401 A273930 A273931 * A196753 A258424 A015431

Adjacent sequences:  A273930 A273931 A273932 * A273934 A273935 A273936




John Cerkan, Jun 04 2016



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

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 7 19:52 EDT 2020. Contains 336279 sequences. (Running on oeis4.)