A338476 Primes of the form 398*x^2-1.
397, 3581, 6367, 9949, 14327, 19501, 25471, 32237, 39799, 48157, 67261, 78007, 115021, 128951, 143677, 159199, 192631, 229247, 248749, 290141, 312031, 334717, 433421, 460087, 544861, 574711, 735901, 770527, 842167, 879181, 1035197, 1076191, 1160567, 1203949, 1338871, 1385437, 1432799, 1786621
Offset: 1
Keywords
Examples
a(3) = 398*4^2-1 = 6367 is prime.
Links
- V. Granville, Quadratic progressions with very high prime density, MathOverflow.
Programs
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Maple
select(isprime, [seq(398*x^2-1,x=1..1000)]);
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Mathematica
Select[398 Range[100]^2-1,PrimeQ] (* Harvey P. Dale, Jan 13 2023 *)
Formula
a(n) = 398*A338477(n)^2-1.
Comments