%I A138341
%S A138341 1,2,7,7,2,13,13,2,19,19,2,25,25,2,31,31,2,37,37,2,43,43,2,49,49,2,55,
%T A138341 55,2,61,61,2,67,67,2,73,73,2,79,79,2,85,85,2,91,91,2,97,97,2,103
%V A138341 1,-2,-7,-7,2,13,13,-2,-19,-19,2,25,25,-2,-31,-31,2,37,37,-2,-43,-43,2,
               49,49,-2,-55,
%W A138341 -55,2,61,61,-2,-67,-67,2,73,73,-2,-79,-79,2,85,85,-2,-91,-91,2,97,97,
               -2,-103
%N A138341 Expansion of (1-4x-x^3)/(1-x+x^2)^2.
%C A138341 Hankel transform of A079309.
%F A138341 a(n)=(2n+1)cos(pi*n/3)-(2n+5)*sin(pi*n/3)/sqrt(3);
%Y A138341 Cf. A138342.
%Y A138341 Sequence in context: A153738 A159790 A016639 this_sequence A153520 A153649 
               A020770
%Y A138341 Adjacent sequences: A138338 A138339 A138340 this_sequence A138342 A138343 
               A138344
%K A138341 easy,sign
%O A138341 0,2
%A A138341 Paul Barry (pbarry(AT)wit.ie), Mar 15 2008