%I A075615
%S A075615 1,0,2,1,0,8,0,8,1,0,18,0,48,0,32,1,0,32,0,160,0,256,0,128,1,0,50,0,400,
               0,
%T A075615 1120,0,1280,0,512,1,0,72,0,840,0,3584,0,6912,0,6144,0,2048,1,0,98,0,1568,
               0,
%U A075615 9408,0,26880,0,39424,0,28672,0,8192,1,0,128,0,2688,0,21504,0,84480,0,
               180224,0
%V A075615 1,0,-2,1,0,-8,0,8,1,0,-18,0,48,0,-32,1,0,-32,0,160,0,-256,0,128,1,0,-50,
               0,400,0,
%W A075615 -1120,0,1280,0,-512,1,0,-72,0,840,0,-3584,0,6912,0,-6144,0,2048,1,0,-98,
               0,1568,0,
%X A075615 -9408,0,26880,0,-39424,0,28672,0,-8192,1,0,-128,0,2688,0,-21504,0,84480,
               0,-180224,0
%N A075615 Let P(k,X)=prod(i=1,2*k, X-1/cos(Pi*(2*i-1)/(4*k)) ) which is a polynomial 
               with integer coefficients. Sequence gives array of coefficients for 
               P(k,X).
%C A075615 included in A053120
%Y A075615 Sequence in context: A117651 A109971 A021896 this_sequence A076341 A110510 
               A051122
%Y A075615 Adjacent sequences: A075612 A075613 A075614 this_sequence A075616 A075617 
               A075618
%K A075615 easy,sign
%O A075615 1,3
%A A075615 Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 11 2002