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A059842
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The next square after a(n)^3 is a(n+1)^2.
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3
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1, 2, 3, 6, 15, 59, 454, 9674, 951501, 928140821, 28276184777782, 150359618976700758746, 1843727887745124274995859697327, 2503486403859294888221025578988349446337176495, 125261571430858575370252424686453280425035047529321451018103304969551
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n+1) = min { i | i^2 > a(n)^3 }.
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EXAMPLE
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a(4) = 6 has cube 216. The next square is 225 = 15^2. So a(5) = 15.
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MAPLE
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a := proc(n) option remember: if n=1 then RETURN(1) fi: if n=2 then RETURN(2) fi: ceil(a(n-1)^((3.)/(3-1))): end: Digits := 200: for n from 1 to 20 do printf(`%a, `, a(n)) od:
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MATHEMATICA
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f[n_Integer] := Floor[ N[ Sqrt[n^3] ] ] + 1; NestList[f, 1, 15]
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PROG
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(PARI) { a=0; for (n=1, 21, write("b059842.txt", n, " ", a=floor(sqrt(a^3)) + 1); ) } \\ Harry J. Smith, Jun 29 2009
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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