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A074820 Numbers n such that mu(n) = mu(n+2). 1
3, 5, 11, 16, 17, 18, 25, 29, 33, 41, 48, 50, 52, 54, 55, 59, 71, 85, 88, 90, 91, 93, 96, 98, 101, 103, 105, 107, 124, 126, 137, 141, 143, 148, 149, 150, 159, 160, 162, 163, 165, 169, 179, 183, 185, 191, 193, 195, 196, 197, 198, 201, 203, 213, 215, 217, 219, 227 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) seems to be asymptotic to c*n with c near 3.73. Probably c = 1/(3A/2 + 1 - 12/pi^2) ~ 3.729994018, where A ~ 0.322634099 is the product over all primes p of 1 - 2/p^2.

LINKS

Table of n, a(n) for n=1..58.

MATHEMATICA

Select[Range[230], MoebiusMu[ # ]==MoebiusMu[ #+2]&]

Flatten[Position[Partition[MoebiusMu[Range[250]], 3, 1], _?(#[[1]]==#[[3]]&), {1}, Heads->False]] (* Harvey P. Dale, Mar 08 2015 *)

CROSSREFS

Cf. A008683.

Sequence in context: A322439 A018313 A219039 * A327043 A006169 A323582

Adjacent sequences:  A074817 A074818 A074819 * A074821 A074822 A074823

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Sep 08 2002

EXTENSIONS

Edited by Dean Hickerson, Sep 10 2002

STATUS

approved

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Last modified July 12 16:03 EDT 2020. Contains 335665 sequences. (Running on oeis4.)