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%I #8 May 22 2019 10:19:37
%S 0,1,-1,0,3,-9,18,-27,27,1,-92,309,-771,1716,-3627,7449,-14897,28764,
%T -52921,91239,-143718,196197,-196197,0,737817,-2785484,7758154,
%U -18894735,42409968,-89718894,180879813,-349599492,650139687,-1166803109,2028578278
%N First term of n-th difference sequence of (floor(k*r)), r = sqrt(1/2), k >= 0.
%H Clark Kimberling, <a href="/A325729/b325729.txt">Table of n, a(n) for n = 1..200</a>
%t Table[First[Differences[Table[Floor[Sqrt[1/2]*n], {n, 0, 50}], n]], {n, 1, 50}]
%Y Cf. A325664.
%K easy,sign
%O 1,5
%A _Clark Kimberling_, May 19 2019