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%I #10 Nov 29 2023 06:58:14
%S 0,0,-1,0,0,1,0,0,-1,-1,0,0,0,1,1,0,0,0,-1,-1,-1,0,0,0,0,1,1,1,0,0,0,
%T 0,-1,-1,-1,-1,0,0,0,0,0,1,1,1,1,0,0,0,0,0,-1,-1,-1,-1,-1,0,0,0,0,0,0,
%U 1,1,1,1,1,0,0,0,0,0,0,-1,-1,-1,-1,-1,-1,0,0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,0,0,-1,-1,-1,-1,-1,-1,-1,0,0,0,0,0,0,0
%N Differences between A072781 and A072738.
%H Boris Putievskiy, <a href="http://arxiv.org/abs/1212.2732">Transformations [of] Integer Sequences And Pairing Functions</a>, 2012, arXiv:1212.2732 [math.CO], 2012.
%F From _Boris Putievskiy_, Jan 16 2013: (Start)
%F a(n) = floor((2*A000027(n)-A003056(n)^2-A003056(n))/(A003056(n)+3))*(-1)^A003056(n).
%F a(n) = floor((2*n-t*t-t)/(t+3))*(-1)^t where t=floor((-1+sqrt(8*n-7))/2).
%F (End)
%o (Scheme) (define (A072785 n) (- (A072781 n) (A072738 n)))
%Y Cf. A130517, A162630.
%K sign,tabl
%O 0,1
%A _Antti Karttunen_, Jun 12 2002