Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #14 Mar 15 2021 09:53:18
%S 2,3,5,8,10,14,17,21,26,30,36,41,47,54,60,68,75,83,92,100,110,119,129,
%T 140,150,162,173,185,198,210,224,237,251,266,280,296,311,327,344,360,
%U 378,395,413,432,450,470,489,509,530,550,572,593,615,638,660,684,707,731,756,780,806,831,857,884,910,938,965,993,1022,1050,1080,1109,1139,1170,1200,1232,1263,1295,1328,1360
%N a(n) = n + ceiling( (1/5)*n^2 ). Complement of A183870.
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,1,-2,1).
%F a(n) = floor( (n+1)*(n+4)/5 ). [_Bruno Berselli_, Mar 05 2014]
%t a=5; b=-5;
%t Table[n+Floor[(a*n+b)^(1/2)],{n,100}]
%t Table[n-1+Ceiling[(n*n-b)/a],{n,80}]
%Y Cf. A183870.
%K nonn,easy
%O 1,1
%A _Clark Kimberling_, Jan 07 2011