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A217565
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The smallest prime p that with its successor q gives prime counts of all ten base-10 digits for the expression (q^prime(n))*(p^prime(n+1)).
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0
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33581, 673, 571, 1987, 915199, 441799, 2115761, 961943, 15406687, 77123341, 4098427, 5526679, 54560189, 22291639, 371594479, 126499693, 229299227, 103196347, 37851677, 1198387109, 801422893, 966240103, 281430131, 926679973, 154019941, 196449137, 243985993
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OFFSET
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1,1
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COMMENTS
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This reverses the idea for A217049, with the smaller of successive primes being raised to the larger prime power. See that sequence for motivation.
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LINKS
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EXAMPLE
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(677^3)*(673^5) is the value corresponding to a(2). What this means is that the decimal representation of this number has a prime number of copies of each digit and no pair of successive primes in the same order and smaller than {673,677} has the same characteristic.
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MATHEMATICA
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Table[p=2; While[!And@@PrimeQ[DigitCount[(p^Prime[n+1])*(NextPrime@p^Prime[n])]], p=NextPrime@p]; p, {n, 6}] (* Giorgos Kalogeropoulos, Aug 18 2021 *)
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PROG
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(Python)
from sympy import isprime, nextprime, prime
from sympy.ntheory import count_digits
def a(n):
pn = prime(n); qn = nextprime(pn)
p, q = 2, 3; c = count_digits((q**pn)*(p**qn))
while not all(isprime(c[i]) for i in range(10)):
p, q = q, nextprime(q); c = count_digits((q**pn)*(p**qn))
return p
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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