A063870 Numbers n such that sigma(n) - usigma(n) = 3n/2.

480, 2688, 2095104, 16854816, 41055200, 1839272960, 5905219584, 204004720640

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Prog

(PARI) u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)); for(n=1, 10000, if(sigma(n)-u(n)==3*n/2, print(n)))

Crossrefs

Cf. A034448, A000203, A048146, A063846, A064591.

Sequence in context: A253401 A327944 A357493 * A329536 A331768 A035314

Adjacent sequences: A063867 A063868 A063869 * A063871 A063872 A063873

Keyword

nonn

Author

Jason Earls, Aug 27 2001

Extensions

More terms from Dean Hickerson, Sep 25 2001

There are no others less than 1.5*10^13, but here's a larger one: 948990933336933380096. - Dean Hickerson, Sep 25 2001

Status

approved