%I #16 Jan 14 2021 20:00:48

%S 2,3,5,6,8,9,15,18,20,23,26,30,35,39,56,156,176,251,306,308,431,548,

%T 680,2393,2396,2925,3870,4233,5345,6125,6981,7224,9734,17724,18389,

%U 22253,25584,28001,40835,44924,47411,70028,74045

%N Numbers k such that L(2*k + 1) is prime, where L(m) is a Lucas number.

%C For n = 24..43, we can only claim that L(2*a(n) + 1) is a probable prime. Sequence arises in a study of A269254; for detailed theory, see [Hone]. - _L. Edson Jeffery_, Feb 09 2018

%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.

%e If k = 56, then L(2*k + 1) is a prime with twenty-four digits.

%Y Cf. A000032, A001606, A269251, A269252, A269253, A269254.

%Y Cf. A294099, A298675, A298677, A298878, A299045, A299071, A285992, A299107, A299109, A088165, A299100, A299101, A113501.

%K nonn,hard

%O 1,1

%A _Parthasarathy Nambi_, Apr 26 2006

%E Values beyond 680 from _L. Edson Jeffery_, et al., Feb 02 2018