A219277 - OEIS

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

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OFFSET

1,1

COMMENTS

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

The corresponding primes are in A144132.

LINKS

Table of n, a(n) for n=1..56.

MATHEMATICA

lst={}; Do[If[PrimeQ[ChebyshevT [8, n]], AppendTo[lst, n]], {n, 10^3}]; lst

PROG

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