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Search: id:A156430
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A156430 Number of nXn arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 2. +0
1
1, 2, 10, 12, 84, 132, 954, 1728, 13290, 26820, 217500, 481320, 4086600, 9783480, 86549820, 221921280, 2037627900, 5552479800, 52745205240, 151802154000, 1487961422640, 4500041903280, 45412066438200, 143712079822080 (list; graph; listen)
OFFSET

2,2
CROSSREFS

Sequence in context: A106455 A055697 A055705 this_sequence A095914 A045218 A058216

Adjacent sequences: A156427 A156428 A156429 this_sequence A156431 A156432 A156433

KEYWORD

nonn

AUTHOR

Ron Hardin (rhhardin(AT)att.net) Feb 09 2009

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.

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