The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A040002 Continued fraction for sqrt(5). 12
 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Decimal expansion of 11/45. - Natan Arie Consigli, Jan 19 2016 LINKS Harry J. Smith, Table of n, a(n) for n = 0..20000 G. Xiao, Contfrac FORMULA a(n) = 4 - 2*(binomial(2*n,n) mod 2), with n>=0. - Paolo P. Lava, Jun 11 2009 a(0) = 2, a(n) = 4 n>0. - Natan Arie Consigli, Jan 19 2016 EXAMPLE 2.236067977499789696409173668... = 2 + 1/(4 + 1/(4 + 1/(4 + 1/(4 + ...)))). - Harry J. Smith, Jun 01 2009 MAPLE Digits := 100: convert(evalf(sqrt(N)), confrac, 90, 'cvgts'): MATHEMATICA ContinuedFraction[Sqrt[5], 300] (* Vladimir Joseph Stephan Orlovsky, Mar 04 2011 *) PadRight[{2}, 120, {4}] (* Harvey P. Dale, Jul 06 2019 *) PROG (PARI) { allocatemem(932245000); default(realprecision, 26000); x=contfrac(sqrt(5)); for (n=0, 20000, write("b040002.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 01 2009 CROSSREFS Cf. A002163 (decimal expansion). Continued fraction for sqrt(a^2+1) = (a, 2a, 2a, 2a....): A040000 (contfrac(sqrt(2)) = (1,2,2,...)), A040002, A040006, A040012, A040020, A040030, A040042, A040056, A040072, A040090, A040110 (contfrac(sqrt(122)) = (11,22,22,...)), A040132, A040156, A040182, A040210, A040240, A040272, A040306, A040342, A040380, A040420 (contfrac(sqrt(442)) = (21,42,42,...)), A040462, A040506, A040552, A040600, A040650, A040702, A040756, A040812, A040870, A040930 (contfrac(sqrt(962)) = (31,62,62,...)). Sequence in context: A105192 A345438 A203638 * A151798 A334897 A035684 Adjacent sequences:  A039999 A040000 A040001 * A040003 A040004 A040005 KEYWORD nonn,cofr,easy,cons AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 1 02:46 EST 2021. Contains 349426 sequences. (Running on oeis4.)