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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.
5
39, 36, 30, 21, 21, 15, 27, 675
OFFSET
0,1
COMMENTS
a(8) and a(9) are greater than 10^10. - Arkadiusz Wesolowski, Oct 27 2018
a(8) <= 3*7215727335550^2 = (A221669(1) + A221669(2) + A221669(3))*16978181966^2. - Arkadiusz Wesolowski, May 21 2022
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
KEYWORD
nonn,fini,hard,more
AUTHOR
STATUS
approved