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A116894 Numbers k such that gcd(k! + 1, k^k + 1) is neither 1 nor 2k+1. 4
1, 5427, 41255, 43755, 208161, 496175, 497135 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
g(n) = gcd(n! + 1, n^n + 1) is almost always equal to 1 or to 2n+1. These are the known exceptions: g(1) = 2, g(5427) = 10453, g(41255) = 129341, g(43755) = 157519, g(208161) = 555097. - Hans Havermann, Mar 28 2006
a(8) > 1000000. - Nick Hobson, Feb 20 2024
LINKS
EXAMPLE
gcd(1! + 1, 1^1 + 1) = 2 and 2 != 2*1 + 1, so 1 belongs to the sequence.
PROG
(C) See Links section in A116893.
CROSSREFS
Sequence in context: A211775 A346177 A363782 * A124629 A222696 A125016
KEYWORD
nonn,hard,more
AUTHOR
Giovanni Resta, Mar 01 2006
EXTENSIONS
a(5) from Hans Havermann, Mar 28 2006
a(6)-a(7) from Nick Hobson, Feb 20 2024
STATUS
approved

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Last modified March 28 08:12 EDT 2024. Contains 371236 sequences. (Running on oeis4.)