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A242789 Least number k > 1 such that (k^k-n)/(k-n) is an integer. 0
2, 3, 2, 2, 3, 3, 3, 4, 3, 4, 3, 6, 4, 7, 3, 4, 5, 4, 7, 5, 5, 4, 7, 9, 4, 7, 3, 7, 5, 13, 5, 4, 9, 12, 5, 6, 10, 16, 9, 4, 9, 16, 7, 5, 5, 4, 10, 13, 7, 7, 11, 13, 5, 9, 7, 6, 5, 12, 19, 9, 11, 17, 7, 7, 5, 11, 4, 16, 9, 5, 11, 16, 9, 13, 15, 13, 9, 12, 7, 31, 6, 16, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) <= n+1 for all n.

LINKS

Table of n, a(n) for n=1..83.

EXAMPLE

(2^2-8)/(2-8) = -4/-6 is not an integer. (3^3-8)/(3-8) = 19/-5 is not an integer. (4^4-8)/(4-8) = 248/4 = 62 is an integer. Thus a(8) = 4.

PROG

(PARI) a(n)=for(k=2, n+1, if(k!=n, s=(k^k-n)/(k-n); if(floor(s)==s, return(k))));

n=1; while(n<100, print(a(n)); n+=1)

CROSSREFS

Cf. A242787, A242788.

Sequence in context: A256170 A051686 A079294 * A076733 A079643 A329317

Adjacent sequences:  A242786 A242787 A242788 * A242790 A242791 A242792

KEYWORD

nonn

AUTHOR

Derek Orr, May 22 2014

STATUS

approved

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Last modified May 8 15:40 EDT 2021. Contains 343666 sequences. (Running on oeis4.)