A259303 Numbers n such that there exists an x!=n that makes {x,x,n} an amicable multiset.

1560, 7380, 20448, 20664, 22752, 23352, 25248, 26964, 35328, 51360, 100200, 104412, 108792, 135540, 156312, 192096, 232740, 252252, 278460, 310752, 362160, 401688, 492660, 543456, 548592, 588744, 659736, 732060, 767520, 826848, 998712, 999648, 1129440, 1129464

Offset: 1

Author

Jeppe Stig Nielsen, Jun 23 2015

Keywords

• nonn

Comments

We call the multiset {x,x,n} amicable iff sigma(x)=sigma(n)=x+x+n.

For the x values, see A259302.

If the condition x!=n were dropped, the terms from A005820 would also belong here.

Links

• John Cerkan, Table of n, a(n) for n = 1..1742

Crossrefs

Cf. A005820, A259307, A259302, A259304, A259305, A259306, A125490.

Programs

PARI

isOK(n) = x=(sigma(n)-n)/2; x>0 && x!=n && denominator(x)==1 && sigma(x)==x+x+n;