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A242192
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Number of ways to write n^4 as sum of a square and a cube, both > 0.
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4
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0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0
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OFFSET
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1,72
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COMMENTS
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a(n) = number of occurrences of n in A242183;
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LINKS
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EXAMPLE
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a(6) = #{28^2 + 8^3} = 1;
a(72) = #{4941^2 + 135^3, 1728^2 + 288^3} = 2;
a(225) = #{49375^2 + 500^3, 33750^2 + 1125^3, 10125^2 + 1350^3} = 3;
a(1800) = #{3160000^2 + 8000^3, 2835000^2 + 13500^3, 2160000^2 + 18000^3, 648000^2 + 21600^3} = 4;
a(24200) = #{582914112^2 + 147136^3, 564344000^2 + 290400^3, 479160000^2 + 484000^3, 219615000^2 + 665500^3, 42092875^2 + 698775^3} = 5.
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PROG
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(Haskell)
a242192 n = sum $ map (a010052 . (n ^ 4 -)) $
takeWhile (< n ^ 4) $ map (^ 3) [1..]
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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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