A259305 Numbers n such that there exists an x!=n that makes {x,x,x,n} an amicable multiset.

756000, 1220940, 1437480, 1973160, 5019840, 9058140, 9703260, 11058480, 11641680, 13085280, 17089920, 18117000, 19370880, 21282912, 21628080, 25295760, 25585560, 26936640, 27763560, 28191240, 29104200, 29203020, 30450420, 32839560, 33279120, 33398820

Offset

1,1

Comments

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

For the x values, see A259304.

If the condition x!=n were dropped, the terms from A027687 would also belong here.

Links

John Cerkan, Table of n, a(n) for n = 1..1000

Prog

(PARI) isOK(n) = x=(sigma(n)-n)/3; x>0&x!=n&denominator(x)==1&sigma(x)==3*x+n

Crossrefs

Cf. A027687, A259307, A259304, A259302, A259303, A259306, A036471.

Sequence in context: A290161 A244308 A273971 * A172586 A172571 A172670

Adjacent sequences: A259302 A259303 A259304 * A259306 A259307 A259308

Keyword

nonn

Author

Jeppe Stig Nielsen, Jun 23 2015

Status

approved