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A185026 The first bisection of the sequence A002616 of reduced totients. 1
1, 2, 3, 3, 5, 6, 2, 8, 9, 3, 11, 10, 9, 14, 15, 5, 6, 18, 6, 20, 21, 6, 23, 21, 8, 26, 10, 9, 29, 30, 3, 6, 33, 11, 35, 36, 10, 15, 39, 27, 41, 8, 14, 44, 6, 15, 18, 48, 15, 50, 51, 6, 53, 54, 18, 56, 22, 6, 24, 55, 20, 50, 63, 21, 65, 9, 18, 68, 69, 23, 30, 14, 21, 74, 75, 24, 30, 78, 26, 33 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Fixed points n where n=a(n) are n=1, 2, 3, 5, 6, 8, 9, 11,... = A005097.

There are pairs of the consecutive terms of the form (3*k,k): 6,2, 9,3, 15,5, 18,6, 33,11, 54,18, 63,21, 69,23, 78,26, ... . It seems that k is the set of all A174100(n), n>1, plus a few exceptions (like the pair 126, 42).

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5000

FORMULA

a(n) = A002616(2*n+1).

MAPLE

A185026 := proc(n)

        numtheory[lambda](2*n+1)/2 ;

end proc: # R. J. Mathar, Mar 27 2013

MATHEMATICA

Table[ CarmichaelLambda[2*n + 1]/2, {n, 1, 80}] (* Jean-Fran├žois Alcover, Apr 04 2013 *)

CROSSREFS

Sequence in context: A281363 A050976 A053447 * A289630 A023160 A085312

Adjacent sequences:  A185023 A185024 A185025 * A185027 A185028 A185029

KEYWORD

nonn

AUTHOR

Paul Curtz, Dec 24 2012

STATUS

approved

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Last modified February 26 11:49 EST 2020. Contains 332279 sequences. (Running on oeis4.)