

A010474


Decimal expansion of square root of 18.


11



4, 2, 4, 2, 6, 4, 0, 6, 8, 7, 1, 1, 9, 2, 8, 5, 1, 4, 6, 4, 0, 5, 0, 6, 6, 1, 7, 2, 6, 2, 9, 0, 9, 4, 2, 3, 5, 7, 0, 9, 0, 1, 5, 6, 2, 6, 1, 3, 0, 8, 4, 4, 2, 1, 9, 5, 3, 0, 0, 3, 9, 2, 1, 3, 9, 7, 2, 1, 9, 7, 4, 3, 5, 3, 8, 6, 3, 2, 1, 1, 1, 6, 5, 5, 1, 1, 6, 2, 6, 0, 2, 9, 8, 2, 9, 2, 4, 7, 1
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OFFSET

1,1


COMMENTS

Continued fraction expansion is 4 followed by {4, 8} repeated.  Harry J. Smith, Jun 05 2009
3*2^(1/2) = sqrt(18) is also the minimum width of the arms of the cellular automaton described in A294020.  Omar E. Pol, Oct 29 2017
Equals lambda(3) where lambda(n) = n*Product{k=2, n1} k^((nk)/(nk+1)). See Agama link.  Michel Marcus, Apr 02 2020


LINKS

Harry J. Smith, Table of n, a(n) for n = 1..20000
Theophilus Agama, The rockers function, arXiv:2003.13055 [math.GM], 2020.


EXAMPLE

4.242640687119285146405066172629094235709015626130844219530039213972197...  Harry J. Smith, Jun 03 2009


MAPLE

evalf[100](sqrt(18)); # Muniru A Asiru, Feb 12 2019


MATHEMATICA

RealDigits[Sqrt[18], 10, 100][[1]] (* Vladimir Joseph Stephan Orlovsky, Feb 21 2011 *)


PROG

(PARI) default(realprecision, 100); sqrt(18) \\ Harry J. Smith, Jun 03 2009 (modified by G. C. Greubel, Feb 14 2019)
(MAGMA) SetDefaultRealField(RealField(100)); Sqrt(18); // G. C. Greubel, Feb 14 2019
(Sage) numerical_approx(sqrt(18), digits=100) # G. C. Greubel, Feb 14 2019


CROSSREFS

Cf. A040013 (continued fraction).  Harry J. Smith, Jun 03 2009
Sequence in context: A300004 A147973 A278527 * A064887 A114424 A246819
Adjacent sequences: A010471 A010472 A010473 * A010475 A010476 A010477


KEYWORD

nonn,cons


AUTHOR

N. J. A. Sloane


STATUS

approved



