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A344946
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x -> prime(x) iterated prime(n) times, evaluated at n.
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1
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = prime^{prime(n)}(n), with prime^{0}(n) = n and prime^{k}(n) = prime(prime^{k-1}(n)) for 1 <= k <= prime(n).
a(n) = prime(prime(...(n))) {prime(n) times}.
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EXAMPLE
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a(1) = prime(prime(1)) = 3.
a(2) = prime(prime(prime(2))) = 11.
a(3) = prime(prime(prime(prime(prime(3))))) = 709.
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MATHEMATICA
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nterms=6; Table[Nest[Prime[#]&, n, Prime[n]], {n, nterms}]
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PROG
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(Python)
from sympy import prime
def a(n):
iter = pn = prime(n)
for i in range(1, pn): iter = prime(iter)
return iter
(PARI) a(n) = my(p = n); for (k=1, prime(n), p=prime(p)); p; \\ Michel Marcus, Jun 03 2021
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CROSSREFS
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KEYWORD
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nonn,more,hard
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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