%I A106275
%S A106275 2,3,4,5,6,7,21,26,99,158,405
%N A106275 Numbers n for which the absolute value of the discriminant of the polynomial 
               x^n - x^(n-1) -...- x - 1 is a prime times 2^k for some k >=0.
%C A106275 This polynomial is the characteristic polynomial of the Fibonacci and 
               Lucas n-step recursions. Are the n-step recursions different -- in 
               some way -- for the values of n that yield a prime*2^k discriminant? 
               No other n < 10000.
%H A106275 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               Fibonaccin-Step.html">Fibonacci n-Step</a>
%Y A106275 Cf. A106273 (discriminant of the polynomial x^n-x^(n-1)-...-x-1).
%Y A106275 Sequence in context: A024644 A010354 A070759 this_sequence A031054 A153687 
               A142594
%Y A106275 Adjacent sequences: A106272 A106273 A106274 this_sequence A106276 A106277 
               A106278
%K A106275 hard,more,nonn
%O A106275 1,1
%A A106275 T. D. Noe (noe(AT)sspectra.com), May 02 2005