A268854 -id:A268854 - cp's OEIS frontend

30, 21, 18, 15, 39, 120, 435, 541875

Offset: 0

a(7) = 8*A268854(7) + 3.

If a(8) exists, and the central element is a square, then a(8) > 10^21. - Arkadiusz Wesolowski, Sep 01 2024

Andrew Bremner, On squares of squares II, Acta Arithmetica 99 (2001), pp. 289-308.
Multimagic Squares, Magic squares of squares
The Prime Puzzles and Problems Connection, Problem 63
The Prime Puzzles and Problems Connection, Puzzle 79
Arkadiusz Wesolowski, Examples of these magic squares
Wikipedia, Magic square
Index entries for sequences related to magic squares

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

Offset: 0

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

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

19, 16, 15, 32, 73, 153, 1520, 5104, 241801435

Offset: 0

a(8) from Christian Boyer, added by Arkadiusz Wesolowski, Apr 14 2016

cp's OEIS Frontend