%I #9 Sep 06 2022 15:14:15
%S 1,3,4,6,7,8,9,11,12,13,14,15,16,18,19,20,21,22,23,24,25,27,28,29,30,
%T 31,32,33,34,35,36,38,39,40,41,42,43,44,45,46,47,48,49,51,52,53,54,55,
%U 56,57,58,59,60,61,62,63,64,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80
%N Numbers which are not 1 larger than a nonzero square.
%H Harvey P. Dale, <a href="/A164386/b164386.txt">Table of n, a(n) for n = 1..1000</a>
%F {1} U {A000027 \ A002522} (complement of A002522).
%F a(n) = n + floor(sqrt(n-1) + 1/2).
%e For n = 26, a(26) = n + [sqrt(n-1) + 1/2] = 26 + [sqrt(26-1) + 1/2] = 26 + [5.5] = 31.
%t With[{nn=100},Complement[Range[nn],Range[Floor[Sqrt[nn]]]^2+1]] (* _Harvey P. Dale_, Sep 06 2022 *)
%o (PARI) is(n)=!issquare(n-1) || n==1 \\ _Charles R Greathouse IV_, Sep 01 2015
%K nonn,easy
%O 1,2
%A _Jaroslav Krizek_, Aug 14 2009
%E Edited by _R. J. Mathar_, Aug 20 2009
%E Corrected by _Jaroslav Krizek_, Oct 24 2009