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A122478
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Minimum number k>0 such that ((2n+1)^k - (2n-1)^k)/2 is prime.
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2
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3, 13, 3, 3, 5, 3, 17, 3, 163, 3, 3, 109, 3, 13, 19, 5, 3, 3, 1879, 3, 13, 379, 7, 1531, 7, 5, 337, 5, 3, 61, 19, 3, 23, 3, 11, 16417, 163, 23, 3, 5, 3, 3, 3, 5
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OFFSET
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1,1
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COMMENTS
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All a(n) are primes. Corresponding minimal primes of the form ((2n+1)^k - (2n-1)^k)/2 are {13, 609554401, 109, 193, 51001, 433, 44937854708156010721, 769, ...}.
a(46)-a(49) are 17, 5, 31, 3. a(51)-a(61) are 109, 5, 7, 89, 13, 3, 31, 53, 5, 3, 5. a(63)-a(69) are 3, 7, 19, 5, 167, 163, 293. a(71)-a(74) are 3, 3407, 3, 3. a(76)-a(77) are 3, 19.
a(45), a(50), a(62), a(70), a(75) are currently unknown.
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LINKS
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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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EXTENSIONS
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STATUS
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approved
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