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A066361 The floor(n^(.9999))-perfect numbers, where f-perfect numbers for an arithmetical function f is defined in A066218. 0
2, 18, 17816, 116624 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

Table of n, a(n) for n=1..4.

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

MATHEMATICA

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

CROSSREFS

Cf. A066218.

Sequence in context: A208056 A276092 A191554 * A120929 A349886 A007184

Adjacent sequences:  A066358 A066359 A066360 * A066362 A066363 A066364

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Dec 20 2001

STATUS

approved

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Last modified December 9 08:41 EST 2021. Contains 349627 sequences. (Running on oeis4.)