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A125973
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Smallest k such that k^n + k^(n-1) - 1 is prime.
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10
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2, 2, 2, 2, 2, 3, 2, 2, 14, 4, 7, 2, 38, 6, 7, 3, 4, 10, 2, 9, 74, 6, 10, 7, 4, 61, 20, 4, 5, 9, 6, 16, 6, 8, 2, 9, 4, 10, 2, 48, 44, 163, 9, 2, 95, 3, 27, 70, 6, 26, 57, 9, 6, 8, 207, 2, 27, 15, 45, 7, 69, 199, 55, 16, 2, 5, 12, 43, 137, 39, 9, 57, 5, 20, 4, 115, 2, 103, 45, 15, 20, 109
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..82.
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EXAMPLE
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Consider n = 6. k^6 + k^5 - 1 evaluates to 1, 95, 971 for k = 1, 2, 3. Only the last of these numbers is prime, hence a(6) = 3.
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PROG
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(PARI) {m=82; for(n=1, m, k=1; while(!isprime(k^n+k^(n-1)-1), k++); print1(k, ", "))} - Klaus Brockhaus, Dec 17 2006
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CROSSREFS
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Cf. A000040, A045546, A125881-A125885, A125965-A125972, A126017.
Sequence in context: A105068 A120676 A184172 * A189172 A001031 A035250
Adjacent sequences: A125970 A125971 A125972 * A125974 A125975 A125976
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski, Dec 14 2006
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EXTENSIONS
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Edited and extended by Klaus Brockhaus, Dec 17 2006
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STATUS
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approved
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