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%I #8 Jan 19 2015 17:00:14
%S 1,1,3,5,11,7,43,17,57,31,683,13,2731,127,331,257,43691,73,174763,205,
%T 5419,2047,2796203,241,1016801,8191,261633,3277,178956971,151,
%U 715827883,65537,1397419,131071,24214051,4033,45812984491,524287,22366891,61681
%N Sylvester-Jacobsthal cyclotomic numbers.
%C Primitive parts of Jacobsthal numbers A001045.
%H T. D. Noe, <a href="/A105603/b105603.txt">Table of n, a(n) for n=1..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SylvesterCyclotomicNumber.html">Sylvester Cyclotomic Number</a>.
%F a(n)=product{k=1..n-1, if(gcd(n, k)=1, 2+exp(2*pi*I*k/n), 1)}, I=sqrt(-1)
%F a(n) = (-1)^phi(n)*cyclotomic(n, -2) for n >= 2 (for n = 1 this would be 3), with phi(n) = A000010(n). - _Wolfdieter Lang_, Jan 19 2015
%Y Cf. A020501, A001045, A061446 (with references), A008555.
%K easy,nonn
%O 1,3
%A _Paul Barry_, Apr 15 2005
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