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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A036243 Denominator of fraction equal to the continued fraction [ 0, 2, 4, ...2n ]. 5
2, 9, 56, 457, 4626, 55969, 788192, 12667041, 228794930, 4588565641, 101177239032, 2432842302409, 63355077101666, 1776375001149057, 53354605111573376, 1709123738571497089, 58163561716542474402, 2095597345534100575561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..18.

FORMULA

a(n) = b(n+1) where b(n) = K(n,1)*I(0,1) - (-1)^n*I(n,1)*K(0,1), K(n,x) and I(n,x) Bessel functions. # Peter Luschny, Sep 14 2014

MAPLE

b := n -> BesselK(n, 1)*BesselI(0, 1)-(-1)^n*BesselI(n, 1)* BesselK(0, 1); A036243 := n -> b(n+1):

seq(round(evalf(A036243(n), 99)), n=1..18); # Peter Luschny, Sep 14 2014

MATHEMATICA

Table[Denominator[FromContinuedFraction[Range[0, 2n, 2]]], {n, 20}] (* Harvey P. Dale, Feb 18 2016 *)

PROG

(PARI) a(n)=contfracpnqn(vector(n+1, i, 2*i-2))[2, 1]  \\ M. F. Hasler, Feb 08 2011

CROSSREFS

Cf. A036242.

Sequence in context: A318289 A052840 A308380 * A179505 A211205 A277538

Adjacent sequences:  A036240 A036241 A036242 * A036244 A036245 A036246

KEYWORD

frac,nonn

AUTHOR

Jeff Burch

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 29 20:42 EDT 2020. Contains 334710 sequences. (Running on oeis4.)