A219276 Numbers n such that T_4(n) is prime, where T_4(x) = 8x^4 - 8x^2 + 1 is the fourth Chebyshev polynomial (of the first kind).

2, 3, 5, 8, 10, 14, 17, 19, 31, 32, 34, 35, 39, 48, 50, 51, 53, 54, 59, 61, 73, 76, 78, 84, 88, 90, 97, 101, 102, 105, 107, 110, 121, 126, 128, 134, 135, 139, 143, 144, 146, 152, 153, 158, 167, 171, 172, 178, 180, 184, 186, 187, 189, 201, 202, 203, 205, 207

Offset

1,1

Comments

The corresponding primes are in A144131.

Sequence is infinite under Bunyakovsky's conjecture. - Charles R Greathouse IV, May 29 2013

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

filter:= n -> isprime(8*n^4 - 8*n^2+1):
select(filter, [$1..300]); # Robert Israel, Jan 22 2020

Mathematica

lst={}; Do[If[PrimeQ[ChebyshevT [4, n]], AppendTo[lst, n]], {n, 10^3}]; lst

Prog

(PARI) is(n)=isprime(polchebyshev(4, 1, n)) \\ Charles R Greathouse IV, May 29 2013

Crossrefs

Cf. A144131.

Sequence in context: A325548 A094568 A251607 * A183871 A211542 A022955

Adjacent sequences: A219273 A219274 A219275 * A219277 A219278 A219279

Keyword

nonn

Author

Michel Lagneau, Nov 17 2012

Status

approved