login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A075828 Let u(1) = x and u(n+1) = (n^2/u(n)) + 1 for n >= 1; then a(n) is such that u(n) =(b(n)*x + a(n))/(c(n)*x + d(n)) (in lowest terms) and a(n), b(n), c(n), d(n) are positive integers. 4

%I #28 May 21 2020 10:15:40

%S 0,1,1,10,13,138,101,1228,1923,8930,7303,115356,97249,1721846,1484475,

%T 388760,681971,14725926,13093585,308430212,1386466053,1685280806,

%U 1529091919,42052434936,38450390845,226713176794,208661769963

%N Let u(1) = x and u(n+1) = (n^2/u(n)) + 1 for n >= 1; then a(n) is such that u(n) =(b(n)*x + a(n))/(c(n)*x + d(n)) (in lowest terms) and a(n), b(n), c(n), d(n) are positive integers.

%C For x real <> 1 - 1/log(2), Lim_{n -> infinity} abs(u(n) - n) = abs((x - 1)/(1 + (x - 1)*log(2))). [Corrected by _Petros Hadjicostas_, May 18 2020]

%H Petros Hadjicostas, <a href="/A075829/a075829.pdf">Proofs of various results about the sequence u(n)</a>, 2020.

%F From _Petros Hadjicostas_, May 18 2020: (Start)

%F a(n) = A024168(n)/gcd(A024168(n), A024168(n-1)) = A024168(n)/A334958(n) for n >= 2. (Cf. Michael Somos's claim for d = A075829 using A024168.)

%F u(n) = (A024167(n)*x + A024168(n))/(A024167(n-1)*x + A024168(n-1)) for n >= 2. (End)

%o (PARI) u(n) = if(n<2, x, (n-1)^2/u(n-1)+1);

%o a(n) = polcoeff(numerator(u(n)), 0 ,x)

%Y Cf. A075827 (= b), A075829 (= d), A075830 (= c).

%Y Cf. A024167, A024168, A334958.

%K nonn

%O 1,4

%A _Benoit Cloitre_, Oct 14 2002

%E Name edited by _Petros Hadjicostas_, May 06 2020

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 24 06:07 EDT 2024. Contains 371918 sequences. (Running on oeis4.)