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A054773
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Number of nonnegative integer 4 X 4 matrices with sum of elements equal to n, up to rotational symmetry.
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2
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1, 4, 36, 204, 980, 3876, 13596, 42636, 122666, 326876, 817388, 1931540, 4346404, 9360540, 19390548, 38779380, 75136675, 141430680, 259292440, 463991880, 811990680, 1391975640, 2341057896, 3867821640, 6285222804, 10056336264
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: (x^16 - 4*x^15 + 28*x^14 - 12*x^13 + 76*x^12 + 60*x^11 + 196*x^10 - 44*x^9 + 422*x^8 - 44*x^7 + 196*x^6 + 60*x^5 + 76*x^4 - 12*x^3 + 28*x^2 - 4*x + 1)/ ((x - 1)^16*(x + 1)^8*(x^2 + 1)^4).
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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