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A073499
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Numbers n such that n^(n+1) + (n+1)^n is prime.
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5
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..9.
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EXAMPLE
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1^2 + 2^1 = 3 and 2^3 + 3^2 = 17 are the primes corresponding to the first two terms. The next four terms correspond to probable primes of 155, 870, 2487 and 3678 decimal digits.
I proved the primality of the primes corresponding to a(3) and a(4). [Charles R Greathouse IV, Jan 12 2012]
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MATHEMATICA
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Do[ If[ PrimeQ[n^(n + 1) + (n + 1)^n], Print[n]], {n, 1, 1650}]
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PROG
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(PARI) for(n=1, 1650, if(isprime((n^(n+1))+((n+1)^n)), print1(n, ", ")))
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CROSSREFS
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Cf. A072179, A051442.
Sequence in context: A060051 A100421 A195000 * A222826 A123828 A210277
Adjacent sequences: A073496 A073497 A073498 * A073500 A073501 A073502
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KEYWORD
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nonn,hard,changed
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AUTHOR
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Rick L. Shepherd, Aug 05 2002
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EXTENSIONS
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Edited by Robert G. Wilson v, Aug 08 2002
a(7) from Charles R Greathouse IV, Jan 13 2012
a(8) from Charles R Greathouse IV, Jan 17 2012
a(9) found by Alexander Adamchuk, Apr 09 2007 and shown to be a(9) by Charles R Greathouse IV, Jan 27 2012
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STATUS
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approved
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