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A064148 Numbers k such that mu(k) = mu(k+1). 2
2, 8, 14, 21, 24, 27, 29, 30, 33, 34, 38, 41, 42, 44, 48, 49, 57, 63, 66, 70, 75, 78, 80, 85, 86, 93, 94, 98, 99, 101, 102, 109, 113, 116, 118, 120, 122, 124, 125, 130, 133, 135, 137, 138, 141, 142, 145, 147, 152, 158, 168, 171, 173, 175, 177, 181, 188, 190, 201 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

a(n) seems to be asymptotic to c*n with c=3.7.... Using heuristic arguments (cf. A074820): c maybe = 1/(3A/2 + 1 - 12/Pi^2) ~ 3.729994018, where A ~ 0.3226340989 is the product over all primes p of 1 - 2/p^2 (cf. A065474). - Benoit Cloitre, Sep 08 2002

MATHEMATICA

SequencePosition[MoebiusMu[Range[250]], {x_, x_}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 26 2017 *)

PROG

(PARI) j=[]; for(n=1, 500, if(moebius(n)==moebius(n+1), j=concat(j, n))); j

(PARI) { n=0; for (m=1, 10^9, if (moebius(m)==moebius(m + 1), write("b064148.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 09 2009

CROSSREFS

Cf. A074820, A065474.

Sequence in context: A046940 A046939 A082930 * A161464 A211873 A248057

Adjacent sequences:  A064145 A064146 A064147 * A064149 A064150 A064151

KEYWORD

easy,nonn

AUTHOR

Jason Earls, Sep 11 2001

STATUS

approved

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Last modified December 13 03:41 EST 2019. Contains 329968 sequences. (Running on oeis4.)