OFFSET
1,2
COMMENTS
Numbers k such that 2d + k/d is prime for every d|k. Such k must be an odd squarefree number. Primes in the sequence are A045536. - Thomas Ordowski, Nov 16 2017
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
FORMULA
MATHEMATICA
Select[Range[1, 3400, 2], Function[n, AllTrue[Divisors@ n, PrimeQ[2 # + n/#] &]]] (* Michael De Vlieger, Nov 18 2017 *)
PROG
(PARI) is_ok(n)=n=2*n; fordiv(n, d, if(!isprime(d+n/d), return(0))); return(1);
for(n=1, 10^4, if(is_ok(n), print1(n, ", ")));
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt, Jul 10 2014
STATUS
approved