A268856 a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n numbers that are triangular or square.

39, 36, 30, 21, 21, 15, 27, 675

Offset: 0

Author

Arkadiusz Wesolowski, Feb 14 2016

Keywords

• nonn
• fini
• hard
• more

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
• Index entries for sequences related to magic squares

Crossrefs

Cf. A268854, A268855, A269231.