OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..18
FORMULA
EXAMPLE
39 is in this sequence because 39 - 2^(5 - 1) = 31 = 2^5 - 1 and 31 is prime.
MATHEMATICA
Table[Total[Times@@@FactorInteger[PerfectNumber[n]]], {n, 15}] (* Harvey P. Dale, Sep 22 2019 *)
PROG
(PARI) \\ Ochem & Rao: no odd perfect numbers below 10^1500
forprime(p=2, 2281, if(ispseudoprime(t=2^p-1), print1(2^p+2*p-3", "))) \\ Charles R Greathouse IV, Sep 18 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Sep 12 2016
STATUS
approved