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A055386 Smallest factor of (2n)^(2n) + 1. 2
5, 257, 13, 97, 101, 89, 29, 274177, 5, 148721, 5, 17, 53, 449, 17, 641, 13, 17, 5, 17, 5, 41, 29, 769, 41, 89, 13, 17, 5, 17, 5, 59649589127497217, 37, 41, 13, 97, 149, 17, 5, 15361, 5, 1753, 13, 17, 41, 449, 1129, 1153, 5, 17, 5, 1201, 17, 1777, 89, 4993, 41 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

REFERENCES

C. Stanley Ogilvy and John T. Anderson, Excursions in Number Theory. Dover. New York: 1988. Page 82.

LINKS

Walter Nissen, Home Page (listed in lieu of email address)

Is there any value of n other than 1, 2 and 4, such that n^n+1 is a prime?

EXAMPLE

8^8 + 1 = 97 * 257 * 673, so a(4) = 97.

CROSSREFS

Cf. A014566, A055385.

Sequence in context: A002770 A069071 A181397 * A201606 A139000 A061959

Adjacent sequences:  A055383 A055384 A055385 * A055387 A055388 A055389

KEYWORD

nonn

AUTHOR

Walter Nissen Jun 24 2000

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Last modified February 16 21:17 EST 2012. Contains 205971 sequences.