OFFSET
1,1
COMMENTS
LINKS
Martin Møller Skarbiniks Pedersen, Table of n, a(n) for n = 1..1000
EXAMPLE
Number 13 is in sequence because sigma(2*13-1) = sigma(25) = 31 (prime).
PROG
(Magma) [n: n in [1..10000000] | IsPrime(SumOfDivisors(2*n-1))];
(PARI) for(n=1, 10^7, if(isprime(sigma(2*n-1)), print1(n, ", "))) \\ Derek Orr, Sep 25 2014
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Jaroslav Krizek, Sep 24 2014
STATUS
approved