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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).

%I A219276 #10 Jan 22 2020 15:01:46
%S A219276 2,3,5,8,10,14,17,19,31,32,34,35,39,48,50,51,53,54,59,61,73,76,78,84,
%T A219276 88,90,97,101,102,105,107,110,121,126,128,134,135,139,143,144,146,152,
%U A219276 153,158,167,171,172,178,180,184,186,187,189,201,202,203,205,207
%N 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).
%C A219276 The corresponding primes are in A144131.
%C A219276 Sequence is infinite under Bunyakovsky's conjecture. - _Charles R Greathouse IV_, May 29 2013
%H A219276 Robert Israel, <a href="/A219276/b219276.txt">Table of n, a(n) for n = 1..10000</a>
%p A219276 filter:= n -> isprime(8*n^4 - 8*n^2+1):
%p A219276 select(filter, [$1..300]); # _Robert Israel_, Jan 22 2020
%t A219276 lst={}; Do[If[PrimeQ[ChebyshevT [4, n]], AppendTo[lst, n]], {n, 10^3}]; lst
%o A219276 (PARI) is(n)=isprime(polchebyshev(4,1,n)) \\ _Charles R Greathouse IV_, May 29 2013
%Y A219276 Cf. A144131.
%K A219276 nonn
%O A219276 1,1
%A A219276 _Michel Lagneau_, Nov 17 2012