%I A086227
%S A086227 1,2,2,2,4,4,4,6,4,6,8,6,8,8,8,8,12,10,8,16,12,12,16,10,12,18,16,14,16,
%T A086227 16,16,24,16,16,24,18,20,24,16,20,32,22,24,24,24,24,32,28,20,32,24,26,
               36,
%U A086227 24,32,40,28,30,32,30,32,48,32,24,48,34,32,48,32,36,48,36,36,40,40,48,
               48
%V A086227 -1,2,-2,2,-4,4,-4,6,-4,6,-8,6,-8,8,-8,8,-12,10,-8,16,-12,12,-16,10,-12,
               18,-16,14,-16,
%W A086227 16,-16,24,-16,16,-24,18,-20,24,-16,20,-32,22,-24,24,-24,24,-32,28,-20,
               32,-24,26,-36,
%X A086227 24,-32,40,-28,30,-32,30,-32,48,-32,24,-48,34,-32,48,-32,36,-48,36,-36,
               40,-40,48,-48
%N A086227 a(n)=1/(4i)*sum( i^k*tan(k*Pi/4/n)) where 1<=k<=n and (k,n)=1.
%o A086227 (PARI) a(n)=round(real(1/4/I*sum(k=1,4*n,(I^k)*tan(Pi/4/n*if(gcd(k,n)-1,
               0,k)))))
%Y A086227 Sequence in context: A007614 A113402 A054861 this_sequence A079438 A123050 
               A113694
%Y A086227 Adjacent sequences: A086224 A086225 A086226 this_sequence A086228 A086229 
               A086230
%K A086227 sign
%O A086227 2,2
%A A086227 Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 28 2003