OFFSET
1,2
COMMENTS
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
FORMULA
a(n) = A161713(n-1). - Reinhard Zumkeller, Jun 21 2009
MATHEMATICA
Divisors[28] (* Harvey P. Dale, Jun 08 2022 *)
PROG
(PARI) divisors(28) \\ Charles R Greathouse IV, Jun 21 2017
CROSSREFS
KEYWORD
nonn,fini,full,easy
AUTHOR
STATUS
approved