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 #18 Aug 09 2015 02:19:32
%S 0,4,5,6,7,8,8,9,9,10,10,11,11,12,12,13,13,13,14,14,15,15,15,16,16,16,
%T 17,17,17,17,18,18,18,19,19,19,19,20,20,20,20,21,21,21,21,22,22,22,22,
%U 22,23,23,23,23,24,24,24,24,24,25,25,25,25,25,26,26,26,26,26,27,27,27
%N a(n) = ceiling(Pi*sqrt(n)).
%H Vincenzo Librandi, <a href="/A121855/b121855.txt">Table of n, a(n) for n = 0..1000</a> (indices changed and term 1000 added by Ivan Panchenko)
%t Table[Ceiling[Pi Sqrt[n]], {n, 0, 100}] (* _Vincenzo Librandi_, Feb 21 2013 *)
%Y Cf. A121275, A121276.
%K nonn,easy
%O 0,2
%A _Mohammad K. Azarian_, Aug 30 2006
%E Offset corrected by _Ivan Panchenko_, Nov 13 2013