OFFSET
1,1
COMMENTS
a(48) > 100000. - Robert Price, Jul 25 2024
MATHEMATICA
Select[Range[10000], PrimeQ[(2 #)! / (2 (#!)^2) - 1 ] &] (* Vincenzo Librandi, Apr 10 2015 *)
PROG
(Magma) [n: n in [1..700] | IsPrime(Factorial(2*n) div (2*Factorial(n)^2)-1)]; // Vincenzo Librandi, Apr 10 2015
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Hugo Pfoertner, Sep 30 2005
EXTENSIONS
a(22)-a(26) from Vaclav Kotesovec, May 02 2021
a(27)-a(47) from Robert Price, Jul 25 2024
STATUS
approved