OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
a(4) = 7 because 14^2 + 1 = 197 and 14^2 + 3 = 199 which are both prime.
MAPLE
for i from 1 to 1000 do if(isprime(i^2 +1) and isprime(i^2+3)) then print(i/2); end if; end do;
MATHEMATICA
Select[Range[1300], AllTrue[(2#)^2+{1, 3}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jan 15 2016 *)
PROG
(Magma) [n: n in [0..6000] | IsPrime((2*n)^2+1)and IsPrime((2*n)^2+3)] // Vincenzo Librandi, Nov 13 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
Ben Paul Thurston, Oct 06 2006
STATUS
approved