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A081237 Numbers n with no k, 0<k<n, such that mu(n-k)=mu(n)=mu(n+k), where mu=A008683 (Moebius function). 1
1, 2, 3, 4, 6, 9, 15, 21 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A081236(n)=0.

Conjecture: there are no more terms.

Next term, if one exists, exceeds 10000000000. [From Sean A. Irvine, Sep 08 2009]

LINKS

Table of n, a(n) for n=1..8.

CROSSREFS

Sequence in context: A096824 A192488 A089797 * A022159 A022161 A127604

Adjacent sequences:  A081234 A081235 A081236 * A081238 A081239 A081240

KEYWORD

nonn,more

AUTHOR

Reinhard Zumkeller, Mar 11 2003

STATUS

approved

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Last modified May 28 16:14 EDT 2017. Contains 287241 sequences.