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A081357 Sublime numbers, numbers for which the number of divisors and the sum of the divisors are both perfect. 4
12, 6086555670238378989670371734243169622657830773351885970528324860512791691264 (list; graph; refs; listen; history; text; internal format)
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

GĂ©rard 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

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Last modified December 13 17:30 EST 2017. Contains 295959 sequences.