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 A268855 #33 Nov 06 2024 04:51:47 %S A268855 30,21,18,15,39,120,435,541875 %N A268855 a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n squares. %C A268855 a(7) = 8*A268854(7) + 3. %C A268855 If a(8) exists, and the central element is a square, then a(8) > 10^21. - _Arkadiusz Wesolowski_, Sep 01 2024 %H A268855 Andrew Bremner, <a href="http://www.multimagie.com/Bremner2.pdf">On squares of squares II</a>, Acta Arithmetica 99 (2001), pp. 289-308. %H A268855 Multimagic Squares, <a href="http://www.multimagie.com/English/SquaresOfSquares.htm">Magic squares of squares</a> %H A268855 The Prime Puzzles and Problems Connection, <a href="http://www.primepuzzles.net/problems/prob_063.htm">Problem 63</a> %H A268855 The Prime Puzzles and Problems Connection, <a href="http://www.primepuzzles.net/puzzles/puzz_079.htm">Puzzle 79</a> %H A268855 Arkadiusz Wesolowski, <a href="/A268855/a268855.txt">Examples of these magic squares</a> %H A268855 Wikipedia, <a href="https://en.wikipedia.org/wiki/Magic_square">Magic square</a> %H A268855 <a href="/index/Mag#magic">Index entries for sequences related to magic squares</a> %Y A268855 Cf. A221669, A268854, A268856, A269231, A375459. %K A268855 nonn,fini,hard,more %O A268855 0,1 %A A268855 _Arkadiusz Wesolowski_, Feb 14 2016