

A237286


Numbers n such that sigma(n)  n = perfect number (A000396).


1



6, 25, 28, 496, 652, 8128, 10682, 10828, 33550336, 44655764, 8589869056, 8623554304, 137438691328
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OFFSET

1,1


COMMENTS

Also numbers n such that sum of the proper divisors of n (A001065) = perfect number (A000396).
Supersequence of perfect numbers (A000396).
a(14) > 10^12.  Giovanni Resta, Mar 01 2014
Up to a(13), note that the terms that are not perfect are deficient.  Michel Marcus, Mar 12 2014


LINKS

Table of n, a(n) for n=1..13.


EXAMPLE

Number 25 is a term because sigma(25)  25 = 31  25 = 6 (perfect number).


PROG

(PARI) isok(n) = sigma(smn=sigma(n)  n) == 2*smn; \\ Michel Marcus, Mar 01 2014


CROSSREFS

Cf. A000203 (sigma(n)).
Sequence in context: A136606 A074096 A126016 * A046416 A042879 A042495
Adjacent sequences: A237283 A237284 A237285 * A237287 A237288 A237289


KEYWORD

nonn,more


AUTHOR

Jaroslav Krizek, Feb 28 2014


EXTENSIONS

a(10) from Michel Marcus, Mar 01 2014
a(11)a(13) from Giovanni Resta, Mar 01 2014


STATUS

approved



