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Divisors of 28.
11

%I #17 Jun 08 2022 13:25:44

%S 1,2,4,7,14,28

%N Divisors of 28.

%C 28 is the second perfect number A000396(2) and 7 is the second Mersenne prime A000668(2). For the structure of this sequence and its representation in base 2, see A135652. - _Omar E. Pol_, Mar 03 2008

%H <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a>

%F a(n) = A161713(n-1). - _Reinhard Zumkeller_, Jun 21 2009

%t Divisors[28] (* _Harvey P. Dale_, Jun 08 2022 *)

%o (PARI) divisors(28) \\ _Charles R Greathouse IV_, Jun 21 2017

%Y Cf. A000396, A000668, A135652.

%K nonn,fini,full,easy

%O 1,2

%A _N. J. A. Sloane_.