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%I #5 Aug 07 2024 09:19:09
%S 1,-3,6,-9,12,-18,30,-45,60,-90,156,-234,288,-432,846,-1269,1260,
%T -1890,4980,-7470,3912,-5868,33996,-50994,-11688,17532,285720,-428580,
%U -471480,707220,2950830,-4426245,-7902900,11854350,35254980,-52882470,-115143480,172715220,457385220
%N a(n) = [x^n] 2/(3*sqrt(4*x^2 + 1) + 6*x - 1). Alternating row sums of A375025.
%p gf := 2/(3*sqrt(4*x^2 + 1) + 6*x - 1):
%p ser := series(gf, x, 42): seq(coeff(ser, x, n), n = 0..38);
%Y Cf. A375025.
%K sign
%O 0,2
%A _Peter Luschny_, Aug 07 2024