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%I #11 Apr 17 2016 12:18:35
%S 1,2,5,6,8,17,18,20,26,30,45,56,156,176,306,308,548,680,1197,2393,
%T 2396,3870,4397,7224,9734,17724,25584,31793,44924,70028,79760,91544,
%U 96600
%N Values of k such that L(k)*L(k+1)-1 is a prime, where L(k) is the k-th Lucas number (A000032).
%C a(34) > 10^5. - _Robert Price_, Apr 17 2016
%e 2 is in the sequence because L(2)*L(3)-1 = 3*4-1 = 11, which is prime.
%t Select[Range@ 5000, PrimeQ[LucasL@ # LucasL[# + 1] - 1] &] (* _Michael De Vlieger_, Apr 07 2016 *)
%o (PARI)
%o lucas(n) = fibonacci(n+1) + fibonacci(n-1)
%o L=List(); for(k=1, 1000, if(ispseudoprime(lucas(k)*lucas(k+1)-1), listput(L, k))); Vec(L)
%Y Cf. A000032, A271429.
%K nonn,more
%O 1,2
%A _Colin Barker_, Apr 07 2016
%E a(22)-a(33) from _Robert Price_, Apr 17 2016
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