A066361 The floor(n^(.9999))-perfect numbers, where f-perfect numbers for an arithmetical function f is defined in A066218.

2, 18, 17816, 116624

Offset: 1

Author

Joseph L. Pe, Dec 20 2001

Keywords

• nonn
• more

Comments

Despite the closeness of f(n) = floor(n^(.9999)) to floor(n) (which generates the usual perfect numbers), the perfect numbers generated by these functions are quite different.

Links

• J. Pe, On a Generalization of Perfect Numbers, J. Rec. Math., 31(3) (2002-2003), 168-172.

Crossrefs

Cf. A066218.

Programs

Mathematica

f[x_] := Floor[x^(.9999)]; Select[ Range[2, 10^6], 2 * f[ # ] == Apply[ Plus, Map[ f, Divisors[ # ] ] ] & ]