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URL: https://oeis.org/A145053

⇱ A145053 - OEIS

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A145053
One-third of the number of n X n nonnegative integer arrays with every 3 X 3 subblock summing to 2.
0
15, 71, 175, 327, 987, 2079, 3603, 9831, 19947, 33951, 89787, 180615
OFFSET
3,1
COMMENTS
Second differences of (a(3k), a(3k + 1), a(3k + 1)) and (a(3k + 1), a(3k + 2), a(3k + 3)) appear to be 48 * 9^(k - 1). Based on this conjecture, we would have a(15) = 306435. - David A. Corneth, Apr 15 2015
CROSSREFS
Sequence in context: A000475 A253476 A308596 * A168298 A126274 A241234
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, Sep 30 2008
STATUS
approved