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%I #27 Jul 22 2022 07:28:25
%S 2,3,5,6,8,9,15,18,23,53,114,194,564,575,585,2594,3143,4578,4970,9261,
%T 11508,13298,30018,54993,198476
%N Indices of (probable) primes in A030221.
%C From a problem in A269254. For detailed theory, see [Hone].
%C a(25) > 2*10^5. - _Robert Price_, Jul 03 2020
%H Andrew N. W. Hone, et al., <a href="https://arxiv.org/abs/1802.01793">On a family of sequences related to Chebyshev polynomials</a>, arXiv:1802.01793 [math.NT], 2018.
%F A299109(n) = A030221(a(n)). - _R. J. Mathar_, Jul 22 2022
%t -1 + Position[Nest[Append[#, 5 #[[-1]] - #[[-2]] ] &, {1, 6}, 2600], _?PrimeQ][[All, 1]] (* _Michael De Vlieger_, Jul 03 2020 *)
%Y Cf. A269254, A030221, A294099 (row 5).
%Y Cf. A285992, A299107, A299109, A088165, A117522, A299100, A299101, A113501, A269253, A298675, A298677, A298878, A299045, A299071.
%K nonn,hard,more
%O 1,1
%A _L. Edson Jeffery_, _Bob Selcoe_ and _Andrew Hone_, Feb 02 2018
%E a(24) from _Robert Price_, Jul 03 2020