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