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A127837
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Numbers n such that ((n+1)^n-1)/n^2 is a prime.
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4
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OFFSET
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1,1
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COMMENTS
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All terms are primes. Corresponding primes of the form ((n+1)^n-1)/n^2 are listed in A128466(n) = {2, 7, 311, 7563707819165039903, ...}.
It seems that if p is in the sequence then the first three numbers n such that n^2 divides (p+1)^n-1 are: 1, p & ((p+1)^p-1)/p. 2 is in the sequence and the first three terms of A127103 are : 1, 2 & ((2+1)^2-1)/2; 3 is in the sequence and the first three terms of A127104 are : 1, 3 & ((3+1)^3-1)/3; 5 is in the sequence and the first three terms of A127106 are : 1, 5 & ((5+1)^5-1)/5.
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LINKS
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EXAMPLE
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4357 is in the sequence because (4358^4357-1)/4357^2 is prime.
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CROSSREFS
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KEYWORD
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hard,more,nonn
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AUTHOR
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STATUS
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approved
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