OFFSET
1,1
COMMENTS
There are 414 such primes for 1 <= x <= 1000, and 3280 for 1 <= x <= 10000.
LINKS
V. Granville, Quadratic progressions with very high prime density, MathOverflow.
FORMULA
a(n) = 398*A338477(n)^2-1.
EXAMPLE
a(3) = 398*4^2-1 = 6367 is prime.
MAPLE
select(isprime, [seq(398*x^2-1, x=1..1000)]);
MATHEMATICA
Select[398 Range[100]^2-1, PrimeQ] (* Harvey P. Dale, Jan 13 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Oct 29 2020
STATUS
approved