|
| |
|
|
A081357
|
|
Sublime numbers, numbers for which the number of divisors and the sum of the divisors are both perfect.
|
|
4
|
| |
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
a(2) was calculated by K. S. Brown.
|
|
|
REFERENCES
|
J.-M. De Koninck, Those Fascinating Numbers, Amer. Math. Soc., 2009.
M. J. Halm, More Sequences, Mpossibilities 83, April 2003
C. A. Pickover, Wonders of Numbers, p. 215
|
|
|
LINKS
|
Table of n, a(n) for n=1..2.
K. S. Brown, Odd Sublime Numbers (posting to sci.math newsgroup)
K. S. Brown, Sublime Numbers
J. Griffiths, Lopsided numbers, Mathematical Spectrum, 43 (No. 2, 2010/2011), 53-54.
Dean Hickerson, Re: Twelve is special (posting to sci.math newsgroup)
C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review
Gérard Villemin, Nombre sublime (French)
|
|
|
EXAMPLE
|
a(1) = 12 because 12 + 6 + 4 + 3 + 2 + 1 = 28 is perfect and number of divisors, 6, is also perfect.
|
|
|
CROSSREFS
|
Sequence in context: A144546 A165970 A285180 * A127708 A094896 A277118
Adjacent sequences: A081354 A081355 A081356 * A081358 A081359 A081360
|
|
|
KEYWORD
|
hard,nonn,bref,more
|
|
|
AUTHOR
|
Michael Joseph Halm, Apr 20 2003
|
|
|
STATUS
|
approved
|
| |
|
|
