A219277 Numbers n such that ChebyshevT[8,n] is prime.

3, 4, 7, 15, 18, 19, 37, 43, 46, 47, 62, 74, 75, 84, 89, 90, 92, 96, 105, 112, 130, 139, 158, 163, 182, 189, 190, 202, 213, 217, 218, 225, 233, 255, 256, 271, 280, 288, 293, 301, 314, 317, 329, 335, 337, 349, 350, 354, 360, 364, 365, 368, 376, 396, 416, 422

Offset: 1

Author

Michel Lagneau, Nov 17 2012

Keywords

• nonn

Comments

ChebyshevT[8,x] is the 8th Chebyshev polynomial of the first kind evaluated at x.

The corresponding primes are in A144132.

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A144131, A144132.

Programs

Mathematica

lst={}; Do[If[PrimeQ[ChebyshevT [8, n]], AppendTo[lst, n]], {n, 10^3}]; lst
Select[Range[500],PrimeQ[ChebyshevT[8,#]]&] (* Harvey P. Dale, Jul 23 2025 *)

PARI

is(n)=ispseudoprime(polchebyshev(8,1,n)) \\ Charles R Greathouse IV, May 22 2017