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%I #6 May 26 2013 11:13:56
%S -1,0,1,-1,1,-1,1,0,0,0,0,1,-1,1,0,1,-1,1,0,1,0,0,1,1,0,0,2,0,1,0,2,1,
%T 1,0,3,1,1,1,3,2,1,2,3,3,2,2,4,5,1,4,5,5,3,5,6,7,4,6,8,9,5,8,11,10,8,
%U 10,13,13,11,12,17,17,13,16,22,19,19,20,26,26,23,25,33,32,29
%N First differences of A027349.
%C Sequence has the same parity as A000041, the partition numbers, i.e. a(n) is congruent A040051(n) mod 2 (proved by _James A. Sellers_ using generating functions).
%o (PARI) a(n)=polcoeff((1-x)*prod(k=1,n,1+x^(2*k+1),1+x*O(x^n)),n)
%K sign,easy
%O 1,27
%A _Ralf Stephan_, Sep 06 2003
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