This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A122986 #23 Feb 16 2025 08:33:02
%S A122986 0,1,4,9,16,24,25,36,41,44,49,56,64,76,81,84,89,96,100,104,116,121,
%T A122986 124,129,136,144,156,161,164,169,176,184,196,201,204,209,216,224,225,
%U A122986 236,241,244,249,256,264,276,281,284,289,296,304,316,321,324,329,336,344
%N A122986 Squares mod 1000.
%C A122986 Possible last three digits of n^2 (leading zeros omitted).
%C A122986 Range of A174452; A010461 is a subset; and also all squares less than 1000 belong to this sequence; the sequence is finite with A000993(3)=159 terms: a(159)=996 is the last term.
%H A122986 R. Zumkeller, <a href="/A122986/b122986.txt">Table of n, a(n) for n = 1..159</a> (full sequence)
%H A122986 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquareNumber.html">Square Numbers</a>.
%H A122986 <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a>
%e A122986 The last three digits of n^2 can be 000, 001, 236, 241, 996, etc. but not 002, 003, 237, 238, etc.
%p A122986 s:={}: for n from 0 to 999 do s:=s union {n^2 mod 1000}: od: op(s); # _Nathaniel Johnston_, Jun 22 2011
%t A122986 Union[PowerMod[Range[1000], 2, 1000]] (* _Vincenzo Librandi_, Dec 29 2019 *)
%o A122986 (Magma) [n: n in [0..999] | IsSquare(R! n) where R:= ResidueClassRing(1000)]; // _Vincenzo Librandi_, Dec 29 2019
%Y A122986 Cf. A036688, A010382, A010411, A010462, A010421, A174452.
%Y A122986 Cf. A006716, A053975, A027676, A027678, A122987, A122988.
%Y A122986 Row 1000 of A096008.
%K A122986 base,fini,full,easy,nonn
%O A122986 1,3
%A A122986 _Sergio Pimentel_, Sep 22 2006
%E A122986 More terms and additional comments from _Reinhard Zumkeller_, Mar 21 2010
%E A122986 Edited by _N. J. A. Sloane_, Apr 10 2010