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A156432
Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 3.
0
1, 6, 12, 136, 294, 3924, 9712, 156128, 424980, 8019000, 23622288, 509911008, 1609793976, 39027027088, 131023800192, 3518648357632, 12483723152016, 367381371180384, 1370345745388480, 43811251070582400, 171071079764322144
OFFSET
3,2
CROSSREFS
Sequence in context: A102077 A102062 A164584 * A070020 A308565 A341106
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 09 2009
STATUS
approved