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A099351
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Numbers k such that 5*k! - 1 is prime.
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10
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3, 5, 8, 13, 20, 25, 51, 97, 101, 241, 266, 521, 1279, 1750, 2204, 2473, 4193, 5181, 10080
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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k = 5 is here because 5*5! - 1 = 599 is prime.
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MAPLE
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for n from 0 to 1000 do if isprime(5*n! - 1) then print(n) end if end do;
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MATHEMATICA
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PROG
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(Python)
from sympy import isprime
from math import factorial
print([k for k in range(300) if isprime(5*factorial(k) - 1)]) # Michael S. Branicky, Mar 05 2021
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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