|
| |
|
|
A046060
|
|
5-multiperfect numbers.
|
|
19
|
|
|
|
14182439040, 31998395520, 518666803200, 13661860101120, 30823866178560, 740344994887680, 796928461056000, 212517062615531520, 69357059049509038080, 87934476737668055040, 170206605192656148480
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Conjectured finite and probably these are the only terms; cf. Flammenkamp's link. [Georgi Guninski, Jul 25 2012]
|
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n = 1..65 (complete sequence from Flammenkamp)
F. Firoozbakht, M. F. Hasler, Variations on Euclid's formula for Perfect Numbers, JIS 13 (2010) #10.3.1
Achim Flammenkamp, The Multiply Perfect Numbers Page
Fred Helenius, Link to Glossary and Lists
Walter Nissen, Abundancy : Some Resources
Eric Weisstein's World of Mathematics, Multiperfect Number.
|
|
|
EXAMPLE
|
From Daniel Forgues, May 09 2010: (Start)
14182439040 = 2^7*3^4*5*7*11^2*17*19
sigma(14182439040) = (2^8-1)/1*(3^5-1)/2*(5^2-1)/4*(7^2-1)/6*(11^3-1)/10*(17^2-1)/16*(19^2-1)/18
= (255)*(121)*(6)*(8)*(133)*(18)*(20)
= (3*5*17)*(11^2)*(2*3)*(2^3)*(7*19)*(2*3^2)*(2^2*5)
= 2^7*3^4*5^2*7*11^2*17*19
= (5) * (2^7*3^4*5*7*11^2*17*19)
= 5 * 14182439040 (End)
|
|
|
PROG
|
(PARI) is(n)=sigma(n)==5*n \\ Charles R Greathouse IV, Apr 05 2013
|
|
|
CROSSREFS
|
Cf. A000396, A005820, A027687, A046061, A007539.
Sequence in context: A017616 A304234 A134298 * A172595 A172617 A216015
Adjacent sequences: A046057 A046058 A046059 * A046061 A046062 A046063
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Eric W. Weisstein
|
|
|
STATUS
|
approved
|
| |
|
|
