A273931 Amicable 5-tuples: (x1,...,x5) such that sigma(x1)=...=sigma(x5)=x1+...+x5, x1<x2<x3<x4<x5. Sequence gives x3 numbers.

59999219280, 69626138400, 73605331800, 89398663200, 89398663200, 90391981680, 94320626400, 94832992800, 103169959200

Offset

1,1

Comments

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.

Links

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 Weisstein's World of Mathematics, Amicable Triple.

Crossrefs

Cf. A233553, A273928, A273930, A273933, A273934, A273936 (5-tuples).

Cf. A036471 - A036474 and A116148 (quadruples).

Cf. A125490 - A125492 and A137231 (triples).

Sequence in context: A320880 A015401 A273930 * A273933 A196753 A258424

Adjacent sequences: A273928 A273929 A273930 * A273932 A273933 A273934

Keyword

nonn,more

Author

John Cerkan, Jun 04 2016

Status

approved