

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
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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 WFunction
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}] (* JeanFrançois Alcover, Jun 20 2013 *)


CROSSREFS

Sequence in context: A184580 A184622 A195129 * A087067 A166018 A225745
Adjacent sequences: A167386 A167387 A167388 * A167390 A167391 A167392


KEYWORD

nonn,uned


AUTHOR

Stephen Crowley, Nov 02 2009


STATUS

approved



