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%I #5 Jun 09 2019 13:09:28
%S 1,1,-2,4,-8,15,-25,35,-35,0,126,-462,1253,-2989,6615,-13867,27734,
%T -52921,95863,-163115,255493,-352716,379050,-134596,-828875,3407821,
%U -9217717,20837509,-41675018,74480265,-116145145,143502875,-78990635,-286097760,1453179125
%N First term of n-th difference sequence of (round(k*sqrt(2))), k >= 0.
%H Clark Kimberling, <a href="/A325840/b325840.txt">Table of n, a(n) for n = 1..200</a>
%t Table[First[Differences[Table[Round[Sqrt[2]*n], {n, 0, 50}], n]], {n, 1, 50}]
%Y Cf. A325664.
%K easy,sign
%O 1,3
%A _Clark Kimberling_, Jun 09 2019