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A354072
Perfect numbers that are the sum of the divisors of some number.
3
6, 28, 496, 33550336, 8589869056, 137438691328, 2305843008139952128, 2658455991569831744654692615953842176, 191561942608236107294793378084303638130997321548169216, 13164036458569648337239753460458722910223472318386943117783728128
OFFSET
1,1
COMMENTS
The distinct values of A000203(A146542(n)).
Conjecture: 8128 is the only perfect number that is not in this sequence.
LINKS
EXAMPLE
The perfect number 28 is in the sequence because 28 = sigma(12).
sigma(727145809044307968) = sigma(1152771972099211264) = 2305843008139952128.
PROG
(Magma) Set(Sort([&+Divisors(m): m in [1..10^7] | &+Divisors(&+Divisors(m)) eq 2 * &+Divisors(m)]))
CROSSREFS
Intersection of A000396 and A002191.
Sequence in context: A152953 A066239 A097464 * A166998 A038182 A095723
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, May 16 2022
EXTENSIONS
a(8)-a(10) from Amiram Eldar, May 12 2024
STATUS
approved