%I #20 Apr 12 2020 11:35:15
%S 1,4,8,14,21,29,39,50,62,76,91,107,125,144,164,186,209,233,259,286,
%T 314,344,375,407,441,476,512,550,589,629,671,714,758,804,851,899,949,
%U 1000,1052,1106,1161,1217,1275,1334,1394,1456,1519,1583,1649,1716,1784,1854,1925,1997,2071
%N a(n) = n - 1 + ceiling((2/3)*n^2); complement of A183874.
%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,1,-2,1).
%F a(n) = n - 1 + ceiling((2/3)n^2).
%t a=3/2; b=0;
%t Table[n+Floor[(a*n+b)^(1/2)],{n,100}]
%t Table[n-1+Ceiling[(n*n-b)/a],{n,80}]
%t LinearRecurrence[{2,-1,1,-2,1},{1,4,8,14,21},60] (* _Harvey P. Dale_, Apr 12 2020 *)
%Y Cf. A183874.
%K nonn,easy
%O 1,2
%A _Clark Kimberling_, Jan 07 2011