OFFSET
1,1
COMMENTS
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Multiplicative Perfect Number.
FORMULA
MATHEMATICA
Select[Range[2, 200], PrimeQ[DivisorSigma[0, #]^DivisorSigma[0, #] + 1] &] (* Carl Najafi, Oct 19 2011 *)
PROG
(Haskell)
a084116 n = a084116_list !! (n-1)
a084116_list = filter ((== 1) . a084115) [1..]
-- Reinhard Zumkeller, Jul 31 2014
(PARI) is(n)=isprime(n) || numdiv(n) == 4 \\ Charles R Greathouse IV, Oct 19 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 12 2003
EXTENSIONS
Corrected and edited by Carl Najafi, Oct 19 2011
Revised by Reinhard Zumkeller, Jul 31 2014
STATUS
approved