cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A221669 3 x 3 magic square containing seven squares, read by rows.

Original entry on oeis.org

139129, 83521, 319225, 360721, 180625, 529, 42025, 277729, 222121
Offset: 1

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Author

Jonathan Sondow, Jan 21 2013

Keywords

Comments

Apart from trivial modifications, this is the only known 3 x 3 magic square containing seven squares. No 3 x 3 magic square containing eight or nine squares is known.
The seven integer square roots are A221670.

Examples

			[139129 83521 319225
360721 180625 529
42025 277729 222121]
		

Crossrefs

Formula

a(1) = 139129 = 373^2, a(2) = 83521 = 289^2, a(3) = 319225 = 565^2, a(5) = 180625 = 425^2, a(6) = 529 = 23^2, a(7) = 42025 = 205^2, a(8) = 277729 = 527^2.