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A364270
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a(n) = 2^^n + 3^^n, where ^^ indicates tetration.
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0
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OFFSET
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0,1
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COMMENTS
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a(4) has 3638334640025 digits and is too large to show here.
a(n) is prime for n = 0, 1, 2, 3, but it is not known if a(4) is prime.
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LINKS
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FORMULA
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EXAMPLE
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For n = 3, a(3) = 2^2^2 + 3^3^3 = 2^4 + 3^27 = 7625597485003.
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MATHEMATICA
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nmax=3; NestList[2^#&, 1, nmax]+NestList[3^#&, 1, nmax] (* Stefano Spezia, Oct 22 2023 *)
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CROSSREFS
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KEYWORD
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nonn,base,hard
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AUTHOR
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STATUS
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approved
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