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A275272
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a(n) = p - n!, where p is the second smallest prime > n!.
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5
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2, 3, 5, 7, 11, 13, 19, 31, 23, 19, 17, 43, 73, 41, 149, 41, 53, 61, 109, 37, 37, 71, 109, 193, 97, 173, 47, 101, 229, 163, 241, 83, 139, 103, 83, 577, 311, 47, 269, 61, 61, 107, 97, 89, 379, 149, 269, 83, 137, 167, 281, 89, 79, 443, 229, 157, 179, 563, 389
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OFFSET
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1,1
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COMMENTS
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p-n! where p = nextprime(nextprime(n!)).
Is every term a prime?
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LINKS
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FORMULA
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EXAMPLE
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For n = 4, we have n! = 24, so that p = 31 and a(4) = 7.
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MATHEMATICA
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Table[NextPrime[n!, 2] - n!, {n, 1, 150}]
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PROG
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(PARI) a(n) = nextprime(nextprime(n!+1)+1) - n!; \\ Michel Marcus, Mar 05 2022
(Python)
from sympy import factorial, nextprime
def a(n): fn = factorial(n); return nextprime(nextprime(fn)) - fn
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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