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A116894 Numbers k such that gcd(k! + 1, k^k + 1) is neither 1 nor 2n+1. 4
1, 5427, 41255, 43755, 208161 (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. a(6) > 222000. - Hans Havermann, Mar 28 2006

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

gcd(1! + 1, 1^1 + 1) = 2 and 2! = 2*1 + 1, so 1 belongs to the sequence.

CROSSREFS

Cf. A014566, A038507, A067658, A116891, A116892, A116893.

Sequence in context: A124410 A211775 A346177 * A124629 A222696 A125016

Adjacent sequences:  A116891 A116892 A116893 * A116895 A116896 A116897

KEYWORD

nonn,hard,more

AUTHOR

Giovanni Resta, Mar 01 2006

EXTENSIONS

a(5) from Hans Havermann, Mar 28 2006

STATUS

approved

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Last modified June 30 02:41 EDT 2022. Contains 354913 sequences. (Running on oeis4.)