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A167389 (argument(exp(-(log(2)+W(n,-log(sqrt(2))))/log(2)))*log(2)+Im(W(n, -log(sqrt(2)))))/(2*Pi*log(2)) where W is the Lambert W function. 4
2, 3, 5, 6, 8, 9, 10, 12, 13, 15, 16, 18, 19, 21, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 36, 38, 39, 41, 42, 44, 45, 47, 48, 49, 51, 52, 54, 55, 57, 58, 60, 61, 62, 64, 65, 67, 68, 70, 71, 72, 74, 75, 77, 78, 80, 81, 83, 84, 85, 87, 88, 90, 91, 93, 94, 96, 97, 98, 100, 101 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The definition seems unnecessarily obscure. What is really going on here? - N. J. A. Sloane, Nov 13 2009

The complement is A172513 with first differences in A172515. - R. J. Mathar, Feb 27 2010

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Rob Corless, Poster

Rob Corless, Lambert W function

Stephen Crowley, A Mysterious Three Term Integer Sequence Related to a Lambert W Function Solution to a Certain Transcendental Equation [broken link?]

Eric W. Weisstein, MathWorld: Lambert W-Function

Wikipedia, Lambert W function

FORMULA

(argument(exp(-(log(2)+W(n,-(1/2)*log(2)))/log(2)))*log(2)+Im(W(n,-(1/2)*log(2))))/ (2*Pi*log(2))

MAPLE

seq(round(evalf((argument(exp(-(ln(2)+LambertW(n, -(1/2)*ln(2)))/ln(2)))*ln(2)+Im(LambertW(n, -(1/2)*ln(2))))/(2*Pi*ln(2)))), n = 1 .. 100)

MATHEMATICA

a[n_] := (Arg[Exp[-(Log[2] + ProductLog[n, -1/2*Log[2]])/Log[2]]]* Log[2] + Im[ProductLog[n, -1/2*Log[2]]])/(2*Pi*Log[2]); Table[a[n] // Round, {n, 1, 70}] (* Jean-Fran├žois Alcover, Jun 20 2013 *)

CROSSREFS

Sequence in context: A184580 A184622 A195129 * A288373 A087067 A166018

Adjacent sequences:  A167386 A167387 A167388 * A167390 A167391 A167392

KEYWORD

nonn,uned

AUTHOR

Stephen Crowley, Nov 02 2009

STATUS

approved

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Last modified November 18 05:08 EST 2017. Contains 294853 sequences.