login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A105074
Number of ways to fill in an n X n grid such that the digits of each row and each column form a square number.
1
3, 4, 13, 14, 76, 108, 459, 844
OFFSET
1,1
COMMENTS
Leading zeros are forbidden in the rows and columns.
EXAMPLE
The 1 X 1 crosssquare-puzzle is easy; the only solutions are 1, 4, and 9.
The 4 solutions for n=2 are [16/64], [36/64], [64/49], [81/16].
Or, writing them as 2 X 2 matrices,
16 36 64 81
64 64 49 16
CROSSREFS
Sequence in context: A095790 A109474 A053910 * A208847 A278426 A293280
KEYWORD
nonn,base,more
AUTHOR
Matthijs Coster, Apr 29 2005
EXTENSIONS
Corrected and extended by Luca Petrone, Jan 08 2017
STATUS
approved