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 A268856 a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n numbers that are triangular or square. 4
 39, 36, 30, 21, 21, 15, 27, 675 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(8) and a(9) are greater than 10^10. - Arkadiusz Wesolowski, Oct 27 2018 LINKS Andrew Bremner, On squares of squares II, Acta Arithmetica 99 (2001), pp. 289-308. Multimagic Squares, Home Page The Prime Puzzles and Problems Connection, Problem 63 Arkadiusz Wesolowski, Examples of these magic squares Wikipedia, Magic square CROSSREFS Cf. A268854, A268855, A269231. Sequence in context: A268854 A317388 A088344 * A273597 A022995 A023481 Adjacent sequences:  A268853 A268854 A268855 * A268857 A268858 A268859 KEYWORD nonn,fini,hard,more AUTHOR Arkadiusz Wesolowski, Feb 14 2016 STATUS approved

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Last modified December 18 18:34 EST 2018. Contains 318243 sequences. (Running on oeis4.)