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A242787 Numbers n such that (n^n-2)/(n-2) is an integer. 6
1, 3, 4, 5, 16, 17, 37, 121, 257, 436, 457, 1297, 2116, 2557, 2705, 3817, 3857, 4357, 5545, 6481, 7876, 8009, 9217, 10441, 10621, 11953, 16213, 20896, 22897, 23437, 26321, 26797, 27841, 28681, 35209, 43057, 44101, 47521, 47881, 49204, 49681, 51121, 57241, 61921, 62569 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If m is a nonnegative integer then 2^(2^m)+1 is in the sequence. This implies the sequence is infinite. - Jahangeer Kholdi, Dec 06 2014

LINKS

Table of n, a(n) for n=1..45.

EXAMPLE

(5^5-2)/(5-2) = 3123/3 = 1041 is an integer. Thus 5 is a member of this sequence.

PROG

(PARI) for(n=1, 10^6, if(n!=2, s=(n^n-2)/(n-2); if(floor(s)==s, print(n))))

CROSSREFS

Sequence in context: A240670 A048040 A051033 * A031199 A173027 A290014

Adjacent sequences:  A242784 A242785 A242786 * A242788 A242789 A242790

KEYWORD

nonn

AUTHOR

Derek Orr, May 22 2014

STATUS

approved

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Last modified June 1 19:32 EDT 2020. Contains 334762 sequences. (Running on oeis4.)