A090999 Numbers n such that sigma(n)-n = pi(sigma(n)).

1, 15, 21, 33, 23069, 42029, 148031, 209911

Offset

1,2

Links

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

Mathematica

Do[If[DivisorSigma[1, n]-n==PrimePi[DivisorSigma[1, n]], Print[n]], {n, 1, 10000}]

Crossrefs

Sequence in context: A079814 A168354 A190358 * A123912 A346812 A296244

Adjacent sequences: A090996 A090997 A090998 * A091000 A091001 A091002

Keyword

nonn

Author

Naohiro Nomoto, Mar 01 2004

Status

approved